Do They Work — API Quick Start VS Tetra SafeStart?

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There’s an ongoing debate among fishkeepers about whether Tetra’s SafeStart and API’s Quick Start even work.

Soo many products, but which ones work?

What is the difference between Tetra SafeStart and Tetra SafeStart Plus anyway?

Starting a new tank can be stressful for both you and your new fish buddies.

The logic behind these products is solid, but that’s in theory.

Is there a safe dose or an overdose?

Should you do a fishless cycle?

What’s the reality? The good news is I have tested them both…twice.

I’d be more than happy to show you my results and point you in the right direction.

Shall we?

Main differences – API Quick Start versus Tetra SafeStart Plus?

api quick start vs tetra safestart header

Both products claim to have live nitrifying bacteria that will speed up or reinforce your nitrogen cycle.

They contain two stains of beneficial nitrifiers – one that turns the ammonia into nitrites and one that turns said nitrites into harmless nitrates.

Here’s the truth about the Tetra SafeStart vs API Quick Start comparison:

The difference between the two products is that API Quick Start can be used in both freshwater and saltwater aquariums whereas Tetra SafeStart can only be used in freshwater systems by design. These aquarium cycle starters also contain slightly different strains of bacteria, which affects how fast each product works.

Both Tetra Safe Start and API Quick Start will work, given that they are applied in a correct manner. The cycling of a new tank will speed up significantly but it won’t happen overnight.

Generally speaking, with proper use you can realistically expect to wait about 14 days to fully cycle a fish tank with API Quick Start. Tetra SafeStart takes about the same time although often it may finish the process in just 10 days. Dosage plays a major role in success.

Unfortunately, following the instructions on the back is not something that will help, as they are pretty vague.

After experimenting hard I’ve managed to highlight what strengthens your chance for success, eventually finding a process that, in my opinion, is foolproof.

I ran two tests on both before actually using them in a real fish tank project.

The only disappointing part is that they will not cycle your fish tank the same day.

Also, by the “add fish instantly” on the label they don’t mean all the fish the tank can hold but rather just a couple, until the beneficial bacteria settle.

Both API Quick Start and Tetra SafeStart can be added with live fish in the tank.

The bottles obviously don’t contain substrances harmful to fish, just the opposite.

How to use them and make them work?

After running a couple of tests I am confident to share my success formula with you.

Going through hundreds of forum threads and speaking with fishkeepers I know, I did find confirmations of my findings.

This means that my logic was correct.

Tetra SafeStart Plus

Firstly you’d need to get the right bottle of bacteria.

by Cczman

Safe Start and Quick Start both contain live “inactivated” bacteria. By being inactivated like this the products last longer on the shelf and are easier to store, which makes them more beginner-friendly.

Both brands are claiming no refrigeration is needed.

The perfect temperature for the bacteria’s shelf and in-water life would be between 40°F and 80°F (5°C to 25°C).

Going beneath or above that range may spoil it, by killing the microorganisms and rendering the product useless.

Trusting your local fish store is okay, but I do prefer getting mine over at Amazon (link that will open in a new tab).

Anyway, if you do insist on getting the bottles from your local market make sure that they were safely stored and aim to get the most recently shipped ones (with the farthest expiration date).

Some instructions before you start are:

  • Get a bottle that has been manufactured as recently as possible – The newer the bottle, the better. Also, get at least two bottles, I will explain why later.
  • Choose a bottle meant for a larger aquarium than yours – For me, it worked best when I used the 3.38 Oz bottle of Tetra SafeStart Plus for my 20 gallons, and also when I doubled the dose recommended for the API Quick Start.
  • Make sure the ammonia is not already deadly high – everything above 2.5 ppm of ammonia will be harmful to your fish AND the bacteria. Before you start with the nitrogen cycle you need the ammonia lowered as much as possible.

With that out of the way, you can start cycling your aquarium.

Follow these exact steps to properly use Tetra SafeStart or API Quick Start:

  1. Dechlorinate your water no less than 24 hours before adding the bacteria.

    Use a commercial dechlorinator.

    Leave the filters running during that time.

    Chlorine will kill the not well-established cycling bacteria. Also, when having live fish in the tank you first dechlorinate the water and then add it to the tank.

  2. Shake the bottle of bacteria hard.

    This part is really important.

    Shake the bottle really well before adding the bacteria.

  3. Pour in double the recommended dosage.

    For Tetra SafeStart users just add the WHOLE bottle of bacteria to your aquarium.

    Add it all.

    You can’t overdose with aquarium cycle starter products, unlike with dechlorinators and other water conditioners.

    It’s simply beneficial bacteria. The more the better.

  4. Add 1 SMALL fish per 10 gallons of water.

    Adding fish to your new tank should be done shortly after you’ve poured in the bacteria, within a maximum of 2 hours.

    This proportion of fish-to-volume of water is what worked best for me.

    By definition, this is where most people make a mistake and end up with dead fish in their new aquarium.

    Adding just one small fish per 10 gallons of water is the safest way of controlling the ammonia levels. Here you can find some hardy beginner fish options.

    If you’re cycling a 5-gallon tank it’s really best to put a source of ammonia in it and no live fish. Such source could be fish food.

    Anyway, it’s technically true that you can stock the tank up, but you’d need very clean fish (ones that do not poop as much) and you’d have to feed them very carefully to either not overfeed (leaving extra ammonia work for your bacteria) or starve them (being too cautious not to overload your tank with ammonia).

  5. Feed your fish every other day.

    Test your water frequently, if you notice a spike in ammonia it’s okay to not feed your fish that day.

    Many fish can survive more than a week without food, so they will be fine.

  6. Don’t do water changes until the 14th day.

    If and only if the ammonia starts rising for no apparent reason you can do a water change to lower the levels down.

    Add another bottle of the product if that happens.

    This is why I told you to get a second bottle.

    However, there’s another solid reason behind this point.

    You’re probably using chlorinated tap water for your fish tank. In order to perform a water change you’d need to dechlorinate the water first, right?

    Water facilities in the more developed cities use Chloramine instead of Chlorine for disinfection.

    Chloramine represents the chemical bond between chlorine + ammonia.

    Seachem Prime

    Seachem Prime (a commonly used dechlorinator), for example, breaks down chloramine to chlorine and ammonia, takes care of the chlorine, and detoxifies the released ammonia.

    by JustSuppThings

    Every product that claims to detoxify ammonia likely transforms it into ammoniUM.

    Ammonium is harmless to bacteria and fish alike, but the detoxifying effect only lasts for 24 to 48 hours if your tank’s pH is above 7.0. This does not mean that having more than 7.0 pH is bad, it just means that using ammonia detoxifiers in a non-cycled tank is not a good long-term solution.

    Anyway, after that, the ammonium turns back into ammonia, which means you now have more of the latter in the cycling aquarium.

    The more Chloramine your water facility uses, the more the released ammonia after the effect of the detoxifier expires. This could consequently harm your bacterial biofilter and fish if the contents turn out to be too high for the bacteria to handle in time.

    Author’s note: This only affects new aquariums that do not have an established colony of nitrifying bacteria.

    Anyway, another argument for not changing the water in the first 14 days of cycling (unless there’s a dangerous ammonia spike out of nowhere) is that studies suggest that nitrifying bacteria use ammonia instead of ammonium for their source of energy.

    Continuously using a dechlorinator that turns ammonia into ammonium could actually slow down the nitrogen cycle in your aquarium even further. The nitrifying bacteria would not be interested in the latter and will not be stimulated to multiply further.

    This can easily turn into a vicious circle and a never-ending supply of Prime for a new, non-cycled fish tank…

    If you’re using bottled bacteria you’d want your fish tank to cycle as soon as possible, right?

    Tip: The best way to avoid all of this is by having a separate batch of dechlorinated water to use for water changes during aquarium cycling. The “emergency batch” should be dechlorinated at least 24 hours before use. Add a little bit of bottled bacteria to it to make up for the residual ammonia and it’s good to go.

    Suggested Read: How Aquarium Fish could Die After a Large Water Change

    Despite the described scenario Seachem’s Prime still remains a fantastic option for water dechlorination in a fully cycled aquarium. I’d recommend it to anyone who is using tap water for their aquarium. The residual ammonia from breaking down the Chloramine would be negligible to the already-established bacterial colony in a mature tank.

    Anyway, after 14 days of cycling, you can perform a water change the regular way.

  7. Don’t test the water for the first 2 days.

    It’s okay to test it whenever you want but that is something that I stuck with throughout my tests.

  8. Turn the UV lights off for the first day or two.

    Ultraviolet light does affect the bacteria in a negative way.

    For it to successfully establish I’d strongly recommend not turning those lights on the first day after the application (if you have them).

Keeping the fish tank cycled

After the second week you can gradually add fish, but of course, don’t add 10 at a time. This would overwhelm the bacteria.

When doing the first water change the ammonia may go up, as there may be some ammonia in tap water, but I wouldn’t worry about it that much.

The levels should be overall low and should quickly get back to normal within the next 12 hours or so.

Also, don’t freak out if you don’t see your nitrites spike when water testing.

Tetra SafeStart

If you’re using Tetra’s SafeStart the process will skip the nitrites building up and will directly build into nitrates.

by flexed_guitar

Don’t worry if your aquarium becomes cloudy at first.

The water will get clear within two to three days or a week at most.

Seeing cloudy water in a new aquarium at the beginning of its Nitrogen cycling is completely normal and it means that different bacteria are establishing their hierarchy.

Visit the link if you’d like to understand the process in depth. Understanding aquarium microfauna is, in my opinion, a core component of long-term success in fish keeping.

And that’s not an overstatement.

Which of the two should you choose? Which one is the best for your?

This is not one of those posts where I discuss the pros and cons of both products and leave the choice to you.

I have a statement:

Both can be (successfully) used for a start but If you’re starting a brand new empty fish tank and want to establish an environment safe from Ammonia, I’d recommend using Tetra SafeStart.

API Quick Start

If you’re starting a brand new planted tank, doing huge water changes, or adding a lot of fish at once to an already cycled planted tank I’d go for API Quick Start.

by Tobyracer

Tetra SafeStart’s better at handling the nitrites (it virtually skips them) and API Quick Start will normalize the ammonia levels in the water quicker. The latter is more important in a mature tank with many live fish in it.

High ammonia levels may result in your fish staying at the bottom of the tank seemingly gasping in despair (click the link for an in-depth explanation of this behavior in Bettas).

The API Quick Start is more efficient when you have a planted tank as it does not handle the nitrite levels as well as Tetra’s SafeStart. Live aquatic plants prefer ammonia and nitrite over nitrate as their source of nitrogen so, by using API’s product you will both speed up the cycle and let your plants feed on the nitrite.

Note: Between Tetra SafeStart and Tetra SafeStart Plus the difference is only in the concentration of the bacteria. I’m really happy with Using the Plus version, so the instructions will remain the same.

The alternative bottled bacteria for saltwater aquariums is called Bio Spira.

API doesn’t have a saltwater version, you just double the dose.

What’s with the mixed opinions then?

Honestly, it’s probably a human error.

Seeing how (upon proper use) the products kept proving themselves to me and others I spoke to, I can only conclude that.

Then again, the negative reviews pushed me to test them myself, before anything.


Fishkeeping is a hobby that requires some patience.

Whether you choose to go natural or use bottled bacteria products for starting a new fish tank, you will have to wait it out a bit.

There is no shortcut for that, there are only shorter cuts…

Tell me how things unfolded for your new aquarium in the comments.

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Momchil Boyanov is the Founder and now Senior Editor of AquAnswers. He has over 13+ years of experience in keeping home aquariums as well as providing professional aquarium services. Momchil has had his fair share of adventures in aquarium care. He has made MANY mistakes throughout his fishkeeping journey and thus learned A LOT. Through Aquanswers, Momchil shares knowledge about freshwater and saltwater aquariums with the people within this community.

390 thoughts on “Do They Work — API Quick Start VS Tetra SafeStart?”

  1. Hello Momchil
    Hi There! I am a pretty new fish keeper and I am about to start doing this cycling thing that I keep seeing, when I came across your article and wow that makes a lot of sense.
    I am about to buy API Quick Start at my local pet shop. I have a 10 gallon tank and I plan to put 1 betta and 3 platys in the future. I have two main questions

    1) When you said to not panic if I DON’T see Nitrites, isn’t nitrites bad for fish and I should be worried if I see it?

    2) Are 3 Platies ok for the one small fish you said in the article? or should I just put one.

    3) How much ammonia is considered an ammonia spike?

    Thanks if you reply!

    • Hey there Arwynne,

      Glad you’re doing your research and are being responsible.

      So let me answer in order:

      1) What I meant by this is that the natural cycle usually goes through a Nitrite phase that comes after the Ammonia phase. However, with some bacteria starters such as Tetra SafeStart Plus, the cycle skips the Nitrite phase. This means that you see some Ammonia and then right after you start seeing NitrAte.

      2) I’d go with 2 platies for a 10-gallon tank, at most. I know it does not sound like a lot but it’s the safest and most natural way to do it like that. I also recommend checking my article on “when to add fish to a new tank”.

      3) Anything above 0.5 ppm (parts per million) of Ammonia is considered high in a tank that’s already cycled. During cycling you may see 1 ppm, but monitor your fish’s behavior – if they are not acting weird, it’s likely fine. A spike would be a sudden rise like from 0.25 to 1 in a day, as such changes can be very stressful to fish.

      P.S. – Platies are hardy and very adaptable, so a good fish to use for cycling.

      Good luck, Arwynne!


      • Hi Again!

        Hi Momchil! Thanks for answering all my questions! I have one final question to ask and then ill start to do it. Should I be worried about my fish when the Nitrites rise? I will be using API Quick start. Thanks!

        • Hi,

          As long as you follow the instructions – no. The tank should be big enough to “dilute the pollution” and spare your fish the stress.

          Also, don’t forget that you can always add some more bottled bacteria if you feel uncomfortable about your fish.

          P.S. – after the tank is cycled in two weeks, don’t be hasty to add too many new fish at once. Bacteria need time to adjust to the amount of waste produced.

          Good luck on your new aquarium journey.


  2. Hello. I am 9 days into my aquarium.
    6/5 – I followed pet store advice, setup my 13 gallon tank, added aqualife complete water conditioner.
    6/6 – Waited 24 hours. Put in aqualife activate and 1 longfin tetra glofish. He didn’t make it.
    6/7 – Went back to Petstore. Got new fish. Started checking water with useless Tetra test strips. Same thing happened.
    6/8 – Got 2 zebra?? tetras (more bad petstore advice – now I know they were just going to let me sacrifice them deliberately). She said they were “hardier.” When they didn’t seem happy, I returned them the same day. Then I started doing research. Also, my tank got cloudy through that process.

    6/9 – I ordered Dr. Tim’s One and Only, Dr. Tim’s Ammonia, and an API test kit. While waiting for that I added some fish flakes to try to keep some of my existing bacteria.
    6/11 – Got a cycled filter and plants from a local aquarium group. Added filter and plants and began a fishless cycle with the ammonia and one and only (followed dr. Tim’s recipe and dosed to 2 PPM).

    6/12 – PH = 6.6 – 6.8
    Ammonia = 1.0
    Nitrite = 0
    Nitrate 0 (tested several times, saw a slight increase and then back to zero)
    Did a water change w/ aqualife water conditioner to raise PH. Did nothing to PH.

    6/13 –
    PH 6.6 – Added baking soda, got to 7.6
    Ammonia 1.0 Ammonia dropped to .5 after PH rise
    Nitrite 0
    Nitrate 0
    Dosed to 2.5-3 ppm ammonia and added more one and only few hours later

    6/14 –
    PH 7.6
    Ammonia 2.0
    Nitrite 0
    Nitrate 0-2 ppm

    I expected my cycle to speed up with a cycled filter but I am thinking my bacteria had died or something by the time it was put in the tank. I don’t get why nothing is changing. I am testing 2-3 times a day (son reallllllly wants fish).

    I’d appreciate any advice!

    • Don’t chase a pH. If it’s stable, leave it alone. Constantly adjusting it to keep it where you think it needs to be is more harmful to your fish.

  3. Hey Momchil,

    Thank you for this article. I don’t know if you’re still answering posts, but I thought I’d give it a try. First, thank you for these directions. Out of all the confusing info out there, this was the easiest to understand and follow. So I did.

    At first, I set my tank up, conditioned the water and added microbe-lift Nite Out II and 24 hours later the water was slightly hazy/cloudy. I did tons of research and started wondering how the tank was going to cycle without a source of ammonia. Then I came across your article. I followed all steps and added 6 baby guppies; fed them once a day because they were so small. The tank remained cloudy and they stayed at the top of the tank. On the third day, I added a bubble wand and within 24 hours the water cleared. Also On the third day, the ammonia, nitrite and nitrate levels were all 0. The same for the fourth day. On the fifth day, the ammonia spiked to 0.5ppm with no nitrite or nitrates. I added a second bottle of safe start plus, skipped feeding for that day. On the sixth day, the ammonia was 0, the nitrites were 0 and the nitrates were 0.5ppm. Does this mean the tank has completed the cycle? When can I add a couple adult fish? When should I go back to feeding the babies twice a day?

    Thank you again for your help.

    • Hello David,

      Thanks for reaching out.

      You seem to have followed my advice to the T!

      The water parameters seem ok, but I can’t give an opinion without knowing how large your tank is.

      Generally, at the end of the second week of cycling, things are all good. Nitrate should be more than 0.5 ppm because no tank is that clean, but it also depends on the bioload (which is why I need you to tell me the tank’s size). I doubt 5 baby guppies can produce a huge mess but still…

      Anyway, always look at your aquarium as an ecosystem that needs to balance itself from the inside out. What I mean by this is don’t rush to add too many adult fish at once. Adding a lot of fish simultaneously can throw the cycle off balance. The nitrifying bacteria will need their time to build their colonies according to the new bioload (fish waste). Always keep a bottle of beneficial bacteria at hand, especially when adding new fish.

      I’d say wait for one more week and in the meantime – resume feeding the babies but feed them once a day. Two feedings per day can be a bit too much, in my experience, and leads to a dirty tank quicker. Monitor the water’s parameters carefully. After the week has passed, you can add some new fish to the system. I adhere to the rule of adding 5 to 10 inches of fish body length per 10 gallons of water, per week. Five is conservative and ten is pushing it, so keep that in mind. In practice, I would not go over, say, 7 inches of fish per 10 gallons, per week.

      Did I help?


      P.S. – Also to clarify that’s not one 7-inch fish, but rather three 2-inch fishes…

      • Perfect. The tank is 20 gallons. I figured it was low because the babies are small, maybe 3/4 to 1 inch now. My gut told me to wait until next week which would put the tank at 2 weeks with fish and 3 total weeks old. Again, I appreciate your help and experience. I have a ton of questions but I don’t want to overburden. One question to leave you with: I have well water and the pH is 7.2 out of the faucet but 24 hours of deoxygenating it rises to 8.2. The KH is 10 and the GH is 20. With these higher end water chemistry levels, should I keep using the well water for water changes with fish that can tolerate or try to use Remineralized RO water to try to bring the levels down? I don’t want to get into a situation where I struggle every week or two to maintain equilibrium but I also don’t want an environment that is stressful or harmful to the fish. Again, thinks for everything!


        • Well, it entirely depends on the fish you’d like to keep.

          Given your water, Guppies were a sound choice since they enjoy hard water. So do mollies and platies, for example. Do some research on the many species that enjoy hard water and see if they fit your tank idea.

          With remineralized RO water, you’d just have full control over the water hardness and its contents (which minerals cause said hardness).

          • Momchil,

            Again, thanks for everything. The aquarium is beautiful and the fish are growing, active and healthy. I wanted to clarify that in my original comment I stated that the nitrate level was 0.5ppm… it is actually 5.0ppm. Today is day 10 of the process and all numbers are the same… Ammonia 0, Nitrite 0, and Nitrate 5. I still plan on only adding two more fish, probably Dalmation mollies, next weekend. Should I do a water change even if the numbers remain the same or only if the nitrates rise? When preparing water for changes, can I store the water treated with a lid for a few days… is there a length of time to store treated water that is too long? Finally, I hear that mollies can be a little on the messy side… would you recommend a couple of Cory catfish or plecos to help keep the tank clean? Thank you very much, again!

          • Glad to help, David.

            5 ppm of nitrate with guppy babies in a 20-gallon tank is normal for a cycled system. Don’t do needless water changes, in my opinion as they can stress fish to a degree (new water coming in, etc.). If you see that, with the new inhabitants, Nitrate rises consistently over the course of a week => do a water change weekly. Don’t let the increase in Nitrate become too steep though, as removing too much of it at once can also stress fish (it messes up their osmoregulation, which is basically their internal pressure compared to water hardness). Onto your other question – you can store water, sure. A lid is also great because it will prevent algae from forming inside the container, which you don’t want to transfer to your fish tank. Not that it’s bad for the fish, it’s just unsightly and a nuisance to get rid of. For freshwater aquariums, you can store the water for weeks on end if your container is large enough. Finally, Mollies are messy in the context of that they eat like pigs and leave a mess behind and they also produce more waste compared to other fish of their size. Keeping messy fish requires a stable nitrogen cycle so that there are enough bacterial colonies to convert the waste into less toxic Nitrogen compounds. Bottom cleaners will clean up food leftovers and microalgae but the fish waste will remain untouched. Also, bottom feeders are adding to the bioload of the tank. Don’t let this stop you from getting one though, a bottom-feeding fish will, all in all, keep the substrate *visually* clean. However, since the waste will still remain there you should still vacuum the substrate from time to time. You could leave the waste to bacteria, etc. but it will take time to degrade and it can be unsightly on bright-colored substrates or tanks with a bare bottom. Uncleaned waste also weighs on the Nitrogen cycle for a period of time.

            I hope this helps answer some of your questions.

            – Momchil

  4. Hello Author this is very helpful ive learned a lot as a newbie by simply reading this.. however step1 is the most confusing to me hehe… should i wait 24 hours before i put the bottled bacteria? or i should put bacteria before 24hours expires after doing dechlorination.. thank you.. i hope i did not confuse you hehe

  5. Hello there thank you for such a detailed explanation ! A newbie here was wondering if you can help me out with a few question. I would like to introduce a new fish (betta)to my new tank and needed help with the cycling therefore using tetra safe start. Tank is 6 litres with filter and heater

    1 . Can I use tetra aqua safe to condition the water ? Meaning to dechlorinate it to make it safe for the fish

    2. Is it okay to use tetra aqua safe with tetra safe start ? Can I add tetra safe start immediately after tetra aqua safe ? Do I need to add safe start in between water changes ?

    3. If there is an ammonia spike do I add in more tetra safe start or do a water change ?

    3. I’m sorry if I’m questions sound dumb I’m really trying to learn and hope you can help me out

    • Hello Fizzy,

      Asking questions is how you educate yourself 🙂

      1. Yes.
      2. Typically the answer to your first question is yes. Tetra Aqua Safe dechlorinates water and supposedly adds some stuff to enhance the protective coating of fish. However, during cycling, you should treat Tetra Aqua Safe as a dechlorinator and follow the steps I’ve outlined in the article. After the cycle is done – you always dechlorinate first and then add other stuff. And onto your question about TSS and water changes – it is beneficial to add some if you need to change some water while cycling, but it is generally not needed after that. It’s a good idea to add bottled bacteria whenever you add new fish to the tank.
      3. If there’s an ammonia spike you first do the water change and then add tetra safe start. With the water change, you dilute the ammonia content in the water, making it easier on the fish’s gills. Then by adding TSS you introduce more ammonia-converting bacteria to support their existing colonies and, hopefully, prevent another ammonia spike.

      Hope this helps you out. Good luck, Fizzy.

      • Hi momchil ,

        Thank you so much for replying back means a lot !!! This article you have written has helped me and you replying back means a lot . Was wondering if you could help me clarify a with few more things .

        1 . Based on your instructions of decloranaotion , you said I must wait no less than 24 hours . It it okay to wait for 48-72 hours after decloranaotion and then add the tetra safe start the day the fish come . The reason being my fish is most likely coming from overseas and just afraid it may affect the fish if water is dechlorinated for too long

        2. “ Don’t do water changes until the 14th day.”
        “If and only if the ammonia starts rising for no apparent reason you can do a water change to lower the levels down.”

        For this part you mention if amonia starts rising , is this referring to after the water change or before ?

        Also how much percentage of water change would recommend in an emergency scenario and also in the post two weeks cycle scenario ?

        Thank you so much sorry for so many long winded questions just trying my best to not mess up !

        • 1. Once the water is dechlorinated it should be fine. You can wait if you want.

          2. By these statements I mean that, if everything with the cycling goes smoothly, you should not change the water for 2 weeks. However, if during the cycling ammonia starts rising for some reason, then you should do a water change to offset potential damage.

          3. In an emergency – 40 to 50 percent of the tank. Be absolutely sure that the new water is dechlorinated and is the same temperature as the water in the tank, to not stress your fish.

          After the tank is cycled and everything is normal – between 20 and 30 if the tank is not overstocked. Again, make sure the new water doesn’t have widely different parameters than that in the tank.

          Good luck 🙂

          • Thanks so much momchil for being so kind and patient to replying my enquires . Was getting such mixed replies everywhere you were the most helpful ! Genuinely very thankful for you ! Looking forward to my setup ! Cheers !

          • Hi momchil ! Hope you’re good ! Hope you remember me ! I finally got my betta set up my tank dechlorinated it , waited 24 hours . Ammonia was 0 . Other water conditions were good to go as well .
            Added tetra safe start plus to my tank . It’s been 2 days , water is slightly cloudy presuming due to bacterial blood . Did a water test with the tetra 5 in 1 and an ammonia test .
            Nitrate and nitrite showed 0
            Ammonia showed 0 as well
            Is this a good sign or should I be worried ? My fish also seems to be doing good also . As in DOESNT look stressed . I’m sorry again if I sound dumb just thought I could ask for some help . Your page helped me a lot !

          • Hello, all seems fine. Give it time – monitor the ammonia levels and your betta’s behavior.

            Good luck.

      • Hi momchil, just wanted to thank you for you advice and help . My betta is doing great and all your advise was so helpful ! So glad to have come across this thread . Thank you so so much I appreciate it a lot

        • Glad I could help, friend. 🙂

  6. Hey Momchil

    I have finally set up my Mbuna tank 80 Gallon (315 litre)- I placed rocks new and old (from my previous tank full of good bacteria) some plants and 2 cups of substrate in my new tank, i then added a full bottle (250ml) to my tank hour before adding 5 juvenile Mbuna biggest being 5cm in length.
    My question is 1. is this sufficient for bacteria colonies to grow.
    2. When can i add more Mbuna as they are aggressive and i dont want any of my smaller fish to be bullied straight away.

    My plan was to wait 1 week and add another 5 to make 10 in total for this inital month or so. What do you reckon??

    • As an update i have 9 juvenile mbuna in the tank now. Over stocking is prescribed for Mbuna but unsure approach it when starting with TSS

  7. I have fish in (betta 9gal tank w plants and some rocks) using RO water . I have api quick start but haven’t really used it. Can you cycle without ? Or should I start .
    If so , how. One time or daily ?
    Also a 3 gal w 5 cherry reds and added 3 celestrial danios.
    Had larger tanks before and don’t remember anything about cycling. Just did water changes and nothing ever died or got sick. Never used RO water before. Just now because of well water and softener.

  8. Great article, Momchil. I’m a new betta owner and have two questions for you:

    1) How much Tetra SafeStaft Plus would you recommend that I add to a new 3 gallon tank filled with tap water?
    2) If used water conditioner 24 hours ago, not dechlorinator, is that sufficient to start to use the SafeStart Plus?

    Many thanks.

    • Hello and thank you for being a reader of my blog.

      1. Twice or even three times what the bottle recommends for this size of e tank.

      2. Which water conditioner? Unfortunately “water conditioner” is too general. If it dechlorinates the water then yes, you can start cycling with bottled bacteria.

      Good luck!

  9. Hi,

    Great article! But I’m still kind of confused. Let me try and explain what mistakes ive made despite doing what I thought was sufficient research.

    I’ve just recently got in to hobby of fish keeping, but it’s not been the start I’d hoped for. I want to know I’m doing the best for my fish and not slowly killing them.

    I have a fluval Roma 200. Ill stick to Litres as US and UK gallon measurements have me confused. So the tank size is 200L

    For substrate I have some black sand. I spent half a day rinsing it. I have a generous layer of it in the tank. Add to that I have some rhino stone about 6 small pieces and 1 medium (26kg in total). I have the fluval u4 internal filter. I also have one additional sponge filter capable of dealing with 60 gallons (us or uk I haven’t checked). I also have an additional air stone for that all important surface agitation etc. I’m assuming you can’t really over filter, more the merrier right? Because I’m thinking of including another sponge filter. I’m also using the heater provided although the fish I have don’t require one ( oranda gold fish x3). standard LED light

    So that’s set the scene for the set up.

    Tap Water parameters
    PH 7.0
    Ammonia 0.00ppm
    Nitrite 0.00ppm
    Nitrate 0.00ppm

    Tank filled up. Tap conditioner used.

    Quick start (recommend dosage)

    First test
    Ammonia 0.50ppm
    Nitrite 0.00ppm
    Nitrate 0.00ppm
    PH 7.2 range

    Ammonia 0.50ppm
    Nitrite 0.00ppm
    Nitrate 0.00ppm

    Ghost feeding food added. (Pellets) as that’s all I have.

    Ammonia 0.50ppm
    Nitrite 0.00ppm
    Nitrate 0.00ppm

    More food added

    Ammonia 0.50ppm
    Nitrite 0.00ppm
    Nitrate 0.00ppm

    No food this time.

    Ammonia 0.50ppm
    Nitrite 0.00ppm
    Nitrate 0.00ppm

    No food

    Ammonia 0.50ppm
    Nitrite 0.00ppm
    Nitrate 0.00ppm

    Small food added like 2/3 pellets

    Ammonia 0.50ppm
    Nitrite 0.00ppm
    Nitrate 0.00ppm

    Temp increased to 81/27
    More food added (more than any other day)
    Also topped up quick start with same recommended dosage.

    Ammonia 0.50ppm
    Nitrite 0.00ppm
    Nitrate 0.00ppm

    No food added today

    Ammonia 0.50ppm
    Nitrite 0.00ppm
    Nitrate 0.00ppm

    No food added today. There’s loads still in the tank. And it’s smelling bad. I had the food drop into a small glass jar so it wasn’t exactly floating about. Some was but not all.

    So after 10 days I was a bit worried that my cycle had either stalled or didn’t even start. I’m not sure how much fish food I needed to bump the ammonia to 2/3 ppm as the content of the food was in Japanese.

    I decided to start again. I did a 95% water change. The only water left in the tank was the water I couldn’t easily get out. I added the tap water conditioner and the quick api at the same time. Waited and tested the water in the evening.

    Ammonia 0.00ppm
    Nitrite 0.00ppm
    Nitrate 0.00ppm

    I introduced 3 medium sized oranda gold fish. Three fish in 200L tank sounds reasonable doesn’t it? Well that what I told myself. Correct me if I’m wrong. fed them twice. Enough so they could finish the food with in 3/4 minutes.

    I wanted to do a fish less cycle but as you can see I don’t think I was getting anywhere with that. At this point I’m thinking is this the right hobby for me. If I’m this hopeless without fish what am I doing to be like when I have fish.

    I didn’t test today
    But fed the fish x2 again enough for them to sweep up the food with in 3/4 minutes

    Ammonia 0.50ppm
    Nitrite 0.00ppm
    Nitrate 0.00ppm

    Feed x 2


    Ammonia 1.00ppm
    Nitrite 0.00ppm
    Nitrate 0.00ppm

    Feed x2

    Ok so my understanding at this point based on all the reading and YouTube watching I’ve done is that any ammonia is bad for your fish. So at 1ppm I’m worried (wrongly or rightly so I’m hoping you can advise me) I’m not sure what my understanding of the nitrifying bacteria is and how long it should take to establish its self. I think this is where the confusion is kinda settling in.

    Ammonia 1.00ppm
    Nitrite 0.00ppm
    Nitrate 0.00ppm

    I did a 40/50 L water change. tap conditioner to the water I’ve just added. I was thinking since the api quick start shouldn’t be in the water column it wouldn’t hurt to do a partial water change. And just manage the ammonia etc.


    Ammonia 2.00ppm
    Nitrite 0.00ppm
    Nitrate 0.00ppm

    Fed x2

    Ok so at this point I’m getting a little worried. So I introduced some api AMMO LOCK to detoxify the ammonia. since reading the article I know that bacteria don’t like ammonium and prefer ammonia etc. Was this the correct step?

    Fed x2


    Ammonia 2.00ppm
    Nitrite 0.00ppm
    Nitrate 0.00ppm

    Water change 70L

    Test again

    Ammonia 1.00ppm
    Nitrite 0.00ppm
    Nitrate 0.00ppm

    No feed

    Ammonia 1.00ppm
    Nitrite 0.00ppm
    Nitrate 0.00ppm

    Food added.

    What am I doing wrong? Should I add more quick start and just let the bacteria do the work? Should I not do any further water changes for 2 weeks? How often should I feed the fish?

    Apologies for the long comment

    • Hello,

      Good comment, well-structured and formatted, all the info I need is in there.

      Although nothing is certain in this hobby, I’m almost certain you overfeed. You should probably feed once a day (very little amounts). You should also probably feed every other day, to give the beneficial bacteria some time to expand their colonies. Feed slowly so that your fish can eat it all and be mindful of leftover food. In your first attempt, you went over the top with the food, in my opinion. Also, Orandas are messy fish and they create more waste relative to body size (most plecos are the same). Three are okay in this tank if they’re small, but further down the line, you may need to relocate one if they decide to explode in growth… not because of bioload, but rather swimming space.

      Having one more sponge filter would not hurt. It’s the perfect place for beneficial bacteria to gather.

      You did not mention anything of plants in the tank? Assuming you have none because of the goldfish? In that case, as I recommend in the article, I would choose Tetra SafeStart Plus over API.

      As to what to do from here on – Your tank is roughly 52 US gallons, which is the point of reference for most of these products, I think. I would do one last water change to offset the 1 ppm of ammonia if possible, pour in what beneficial bacteria I have left, then I’d carefully feed every other day and let the tank “marinate”.

      Sorry if this is somewhat confusing for a start but don’t give on the hobby just yet.


      • Thank you for the the prompt reply. It’s nice to see someone active despite the article written in 2018. You’ve certainly won me over.

        I’ve started to implement limited feeding with one day on and one day off. I’ll reduce my feeding to once a day too. I guess over feeding is maybe a newcomer issue which I’m probably guilty off too.

        I’m considering plants but need to do a little more research before spending the money and effort.
        I’ve bookmarked the article you written recently about plants etc.

        Ok I’ll attempt another water change and take it from there.

        Thank you

  10. Hello, thanks for this info – super helpful, have been following your suggestions and I have a question.

    I’ve setup my 32g tank with 3 guppies, some plants (Anubias + some quick growers) and API Quick Start as recommended.

    I’m now on day 13, my ammonia level has been pretty constant throughout at around 0.25, nitrites have always been zero and nitrates are slowly creeping closer to 5ppm.

    Two of my guppies have recently started bullying the third quite continuously and I wanted to add a couple more (plus maybe an algae eater). Am I safe to do that or should I wait for ammonia to drop to 0 and nitrates to increase?

    Many thanks!

    • Hello Stan,

      Typically, I would wait just a little longer. However, guppies have very little bioload so I think you may add some more. I would wait with the algae eater, however. If it’s a pleco – they are rather messy.

      Ideally, the water’s parameters should be: 0 ammonia, 0 no2, 10+ no3

      Hope this helps, Stan.

      Good luck.


      • Thank you for prompt and clear reply Momchil.

        I’ve taken your advice and instead of getting an algae eater (was thinking of Siamese Algae Eater) went for a pair of small Nerites. I’ve also added 2 more guppies.

        Since doing that a 3-4 days ago, the ammonia level has actually fallen and now been pretty much zero for two days (wish those API test kits had more resolution). Nitrites have remained at zero and nitrates have remained steady under 5ppm.

        Do I need to worry about nitrates not increasing? I wonder if the tank is cycled but the plants are eating up the nitratesas they get produced… or whether something went wrong with the cycle. I have two medium size Anubias (one Nana, one Frazeri), a set of Rotala Indica stems and another set Ambulia stems.

        I haven’t changed the water yet, and wondering if I should or if that could stall the cycling process (I’m on day 19)

        Thank you!

        Ps. I wanted to add more guppies to stop the 2 bullying the 3rd… instead I now have 4 guppies bullying him! They are all males of 3 different varieties.

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