Best LED Refugium Lights to Grow Massive Chaetomorpha


As far as natural solutions for saltwater fish tanks go, there’s not much that is cooler than refugiums as a form of aquarium filtration. For optimal efficiency in such a setup, you’ll need to provide the best refugium light for your chosen form of macroalgae to grow, usually Chaeto. This way the plant can grow quickly and suck the excess nutrients from the water.

Nice, now that we know that it should be as simple as browsing for some light bulbs, popping them in, and watching our plants get huge.

The problem is, as always, a great number of questions start popping up with little recourse to answer them.

Is a PAR38 bulb better than a classical LED architecture? Does the fixture need to be waterproof or you can pull this one off with a normal grow light?

The sump lights range from premium pricing to cheap ones, but what are you compromising with if you get a more inexpensive one? What would be an adequate choice of light for a small nano refugium? You don’t want to overwhelm the macroalgae and bleach it.

What should you look for when choosing the best lighting for a sump or its refugium?

Let’s get to it.


For a quick overview of the best LED refugium lights reviewed here take a look at this comparison chart:

Light name: Recommended for: Price Bracket:
1. ACKE LED Grow Light nano refugium $
2. MarsHydro LED Grow Light large refugiums $$
3. GrowStar UFO 150W LED small to medium sized refugiums $
4. Kessil H80 Tuna Flora Refugium LED nano refugiums $$$
5. CF Grow 200 W large refugiums $$
6. TaoTronics LED Grow Light Bulb small to medium sized refugiums $
7. Kessil H380 Spectral Halo II medium to large refugiums $$$$$

A complete guide on LED lighting and its role in growing macroalgae

In my trials and tribulations with the macroalgae Chaetomorpha, I found that there’s a huge difference in the amount of growth I get when using a proper setup, versus just any old thing.

That being said, it’s a hardy species; it will grow as long as it is somewhat cared for.

But, to get decent results with Chaetomorpha, and trust me there is a big difference between optimal and suboptimal growth, let’s go over a quick buyer guide:

1. Controllability of Your Lighting Fixture is Helpful

Old school setups wish they had this level of customization.

If you have the option, an LED light system that allows you to control its output is ideal:

I definitely recommend an LED grow system that allows you to control specific light output for Chaetomorpha. This includes tweaking the right spectral quality and intensity for better water penetration. You can seriously hone in on the exact amount of light and schedule that best suits the needs of your refugium and your macroalgae.

This was one of the biggest game-changers for me when I moved onto LED light setups.

You should not take note of the maximum wattage output here though, as the light-emitting diodes produce way more PAR and intensity per Watt than a regular bulb.

Another thing to mention is that they can be turned down but can’t be turned up past a certain amount, so you’ll need something that packs a decent punch, but is, ideally, dimmable.

Don’t let this be the only thing you look for when purchasing a grow light for your refugium.

However, all things being equal, it’s definitely preferable.

2. Size and Style are Important

Way back when I was initially getting into LED lights for my refugium, I didn’t really pay a lot of attention to what was going to sit well with my aquarium which gave me endless headaches.

Be sure you’re good with the size and style of your refugium’s LED lights:

The gist of where the problems lie is when you have a highly focused and small LED light, that seems to put out enough light but not in a wide enough area. This can be good in small refugiums or in certain aquarium setups, but it’s not great if you’re trying to grow in a wide space. You’ll just end up with one clump growing way faster than the rest.

Furthermore, certain LED systems require an area to hang from above your refugium which might be a problem if you’re like me and keep it out in the open.

You can also opt for something like the Par38 style of bulbs, which screw into sockets and allow for the conversion of hoods into an LED system.

I like these and they tend to have a great light spread.

Unfortunately, depending on the socket they are screwing into, it can be suboptimal for the bulbs leading to quicker burn out than they are rated for.

They’re still a good option and are readily available for people with previous refugium light setups.

3. Remember That Kelvin Ratings are a Marketing Gimmick

Not all LEDs produce the same type of light.

When it comes to the lighting industry there’s this thing called Color Correlated Temperature (CCT).

In layman’s terms, this is an artificially unified system that all lighting manufacturers agreed on considering light color.

See, when a black body burns at a certain temperature it emits a certain color of light.

High burning temperatures produce blue, whereas lower temperatures lean more to the red.

It has been established that defined temperatures on the Kelvin scale correspond to defined colors.

Our sun produces white-ish light and burns at approximately 5700 K.

And now comes manufactured lighting.

See, if you buy a fixture that produces 5700 K of light it would mean that it only resembles that color temperature.

The bulb itself will not literally burn at a staggering 5700 K of temperature.

This is where CCT comes into play.

In general, it is used to determine the chromaticity of the light source to the human eye.

“Warm” light means something that leans on the yellow to red range where “cool” means more white or blue-ish.

However, CCT and its produced chromaticity do not correlate with spectrum at all.

Here’s a visual representation of that:

As you can see from this rather complicated graph, point A and point B have the exact same CCT of 3000 K, however, they would appear very different to the human eye.

Point A would light green where point B would have a purple-white hue.

Upon realizing this, manufacturers have agreed to unify the system, so that 5700 K, for example, would mean white light only.

That being said, here’s how Kelvin ratings affect the growth of macroalgae in refugiums:

For macroalgae to thrive in a refugium you need to provide it with the right spectrum wavelengths and not Kelvin ratings. Kelvin measurements are a very crude estimation of spectral quality. You’ll know that your 2000 K bulb produces light in the yellow-ish spectrum, but you’ll have no idea what that means to your Chaeto. LED lights can employ specific light-emitting diodes with defined spectral ranges, which is why they have dominated the grow light industry in recent years.

The first refugium I tried an LED light in, I almost gave up.

I had the tank balanced right, the nitrates were perfect, I was using a tried and true algae food, but my growth was really not great.

Turns out, I made a really basic beginner’s mistake because I didn’t understand LEDs at the time.

My lights in my refugium were mostly producing white light, which is the most readily visible for our eyes.

Chaetomorpha actually grows best in the blue and red range of light.

Full-spectrum lamps may do the job as well, but not nearly as good as a predominantly red diode LED light fixture.

5000 to 6000 K will grow macroalgae, but to get the hulking behemoths that are possible you need to aim for the proper spectrum.

Be doubly sure to check the range of spectrums your lights of choice are producing.

In my reviews below I made sure to only list lights with the correct spectral quality, so you don’t need to spend additional time researching that.

Which brings me to the next section of interest…

4. Finding the Best Grow Light Spectrum for Chaetomorpha

Michigan State University decided to conduct an eye-opening experiment to show which exact light spectrum has the most impact on plant growth.

Chaetomorpha is a green macroalgae that uses photosynthesis, so it makes sense that it would benefit from these same spectra.

You can see how spectrum affects plants in this illustration:

As seen in the picture, the most growth was achieved through the combination of the red and hyper red spectrum.

Another conclusion we could draw from this experiment is that anything that includes 25% or more blue light performed visibly worse than the combination of purely green and red.

Blue is essential for a green plant’s health improving leaf density, but excessive quantities of it will suppress extension growth.

Having said that, the best light spectrum for growing Chaetomorpha macroalgae would be:

  • No less than 50% of red light in the wavelength range of 630 to 700 nanometers.
  • Between 10% and 15% of blue light in the wavelength range of 435 to 495 nanometers.
  • Around 30% of green light in the wavelength range of 500 to 580 nanometers.

Ideally, an LED grow light for a refugium tank that houses Chaeto would contain a majority of red diodes stimulating the growth, and a very few blue ones to support vegetative density.

When you browse grow lights you’ll rarely see ones that contain green diodes, however.

As shown in the experiment above the green spectrum can be successfully substituted with an abundance of red wavelengths when it comes to growth.

For the sake of knowledge, “pure” white light LED diodes contain a decent amount of “green” and peak at around 550 nanometers with another spike in the blue part of the spectrum .

Here’s a picture representing the spectrum in a white light LED diode:

The peak of 550 nanometers in pure white LEDs falls within the green wavelength range on the electromagnetic spectrum. The warm white diodes also have a great amount of this wavelength spectrum, but peak at red (as seen in the picture above).

When it comes to growing Chaeto this would translate to a potential alternative combination of diodes which could produce good results with a majority of red LED chips and a couple of warm white ones, where the latter will supply the blue and green spectral ranges in adequate proportions.

I don’t have a lot of personal experience with the red and warm white combination, but I have seen solid proof of success with the red-plus-blue diodes one in my reef keeping years.

Chaetomorpha has a few requirements that need to be met to grow, but to grow well is another story.

In a sump or external refugium proper grow lights can be a huge boon to the amount of material your Chaeotomorpha produces and filters.

The best grow lights stay around the red spectrum for Chaeto and will sometimes allow for customization on each separate light channel (read color).

In my reviews below I made sure to only select lights that would significantly boost the photosynthetic rates of macroalgae.

5. Consider Light Penetration

Different penetrations of LEDs are appropriate for certain tanks.

Basically what happens is the water refracts a fair amount of light, even in seemingly bright setups, and plants in deeper sections of the tank can end up getting less than you might expect.

There are a few simple things to remember while purchasing LED lighting in regards to its water penetration:

Both the refugium’s depth and water clarity have a direct impact on how much light reaches the macroalgae. The spectrum output also plays a role in water penetration, as shorter wavelengths have deeper water penetration than longer ones.

Generally, the fixtures I’m reviewing will support any refugium that’s at least 18” deep.

Red light gets filtered out from the water and has the least penetration from all the photosynthetically active spectrum.

Here’s an illustration of that:

And here’s how this impacts a refugium that uses macroalgae for aquarium filtration:

Macroalgae falls within three categories of red, blue and green, with each corresponding to the depth they are seen in the ocean.

Chaetomorpha, in particular, is a green macroalgae, which means it thrives in shallower environments.

This automatically supports the statement that it would most benefit from the red light spectrum.

6. Wattage is Misleading

Here’s why wattage in LED lighting is not a good benchmark for potential intensity:

Nowadays LED lights produce way more intensity per Watt than other types of lighting sources. Newer diodes are very energy efficient, which makes the old “watts per gallon” rule obsolete. Because there are different classes of light-emitting diodes with some more powerful and energy-efficient than others Wattage of LED lights is a really poor benchmark for produced intensity.

And speaking of intensity it’s time to expand on that.

7. The point is to outcompete the algae in the display tank

The following anecdote is something that has happened to me personally but I also heard many others confirm it through their experience.

Say, you have a saltwater aquarium with mainly fish and live rock, and you’re using a rather weak bulb on your refugium, which grows Chaeto decently.

At one point you decide to upgrade the lights in your display tank because you want to have a taste of keeping real corals.

You go ahead and buy a more expensive, strong LED fixture and stuff your tank with beautiful corals.

Not long after the Chaeto in your refugium either dies out or stops growing altogether.

Can you guess what happened?

Macroalgae should be able to outcompete other types of algae in the display tank and also “scrub” the excess nutrients from the water. For this to happen your refugium needs a light with an adequate intensity.

The ones I’m about to review provide powerful output, despite being low Watts or leaning towards the cheaper side of things.

What’s the Best LED Refugium Lighting to Grow Colossal Chaeto?

To get the best for your Chaetomorpha and supply it with an adequate refugium light you should know that options vary according to setup, but we can still eliminate this down quite a bit.

We can take a look at the various specs and offerings of some of the leading grow lights on the market and we can narrow down what each of them brings to the table.

Here are the best LED refugium lights to grow massive macroalgae:

1. ACKE LED Grow Light – Best for smaller refugiums on a budget


Click here to see the current price + more photos on Amazon.

I like this light. I really do. It’s an awesome little grow light that works amazingly in a nano refugium set up, like a cubicle that’s no more than 40 gallons.

I figured I’d mention this one first due to the fact that in my initial nano tank trial, this thing basically doubled the growth output from where it was previously.

It also is an excellent choice for a sump tank, depending on the size, as the intensity and spectrum are nice while having a low wattage, producing plenty of light for its size.

The angle is easily adjustable and fits basically any setup, as it can just kind of clamp-on and face wherever you need it to.

It has predominantly red diodes in the 630 and 660 nm wavelengths which is more than ideal for photosynthesis.

It also has a couple of 460 nm blue ones, helping the Chaeto (or any other macroalgae for that matter) to keep its density.

It also has a few warm light ones in the 2700 K range, which further stimulates photosynthesis, as described in the spectrum section above.

Perhaps, this combo of diodes makes this grow light a popular choice for users on your regular reef keeping forum.

The ACKE LED is one of the best options for a refugium light if you have a smaller tank and would like to keep inside a reasonable budget, without compromising with the growth of your macroalgae.

While this nano LED light did bring the best out of my refugium tank I also liked the look of it.

Made my little tank look like something in the background of Star Trek.

It’s not really a great choice for a larger setup, however.

I’d only use it on refugiums that are up to 30 gallons.

There’s no control of output or timer, and it maxes out at a paltry 12 W.

Still, it’s an excellent LED that takes very little space in the sump, just don’t expect a single fixture of these to do the job for refugiums that are larger than 40 gallons or above.

Buy the ACKE LED if you want a cheap but efficient solution for your saltwater aquarium’s filtration.

 Advantages: 
  • Rather cheap
  • Very energy efficient
  • Spectrum is spot on for photosynthesis of green plants and macroalgae
  • Effective spread is 15 x 15 inches which is great for the price
  • Easy installation
  • Compatible with an outlet timer
  • WATERPROOF
 Disadvantages: 
  • No intensity control

2. MarsHydro LED Grow Light – High PAR over Larger Refugiums


Click here to see the current price + more photos on Amazon.

Here’s a beast of a grow light for macroalgae of any type.

A friend of mine ended up using one of these LED lights in a 26-gallon sump that one of the lights went out on.

This was just after my experience with the ACKE LED so I was touting the benefits of LEDs to everyone who would listen at the time.

The difference between a 120 watt LED and a 12 watt LED was like night and day, literally.

This thing is bright.

However, we noticed that it doesn’t get too hot.

Definitely less heat than my friend’s old halogen.

We were able to lower it closer to the tank than his old set up which evidently increased light penetration significantly.

I received a call the next week with him trying to pawn off some of his algae, as the new set up had a compounding effect on the greens in his sump.

It might have been a bit much, to be honest.

I think we could have gone with a lower wattage light to a similar effect.

Definitely one of the best high power LED lights for refugiums and sumps, though it may be overkill for some.

Buy the MarsHydro LED Grow light if you have a larger refugium and a strong lighting over your display tank.

With this fixture, the Chaeto in the refugium will definitely be able to outcompete other algal growth in your display tank while keeping any pods in there happy and erasing any traces of excess nitrates.

You can see how the MarsHydro 300W grows Chaetomorpha in this reef keeper’s refugium, which he uses on his 300 gallon tank:

By E_Aquatics

And here’s how 10 days of Chaeto growth looks like for another user:

By bif24701

 Advantages: 
  • Really powerful, hitting 400+ PAR , 18” off the water surface
  • Spectrum output grows mad Chaeto
  • Extremely budget-friendly for what you get
  • Very good effective spread of almost a foot
  • Ideal for large refugiums
  • Doesn’t get hot
  • Timer-compatible
  • 3 year warranty
 Disadvantages: 
  • No control over intensity (you control it by changing the mounting height)
  • Not waterproof (mount it over a glass top to increase longevity)

3. GrowStar UFO 150W LED – Lots of growth in nano tanks


Click here to see the current price + more photos on Amazon.

Another small LED light here, but in my opinion, this one packs a much bigger punch.

The GrowStar UFO 150 went onto my own refugium, which was a standard 26-gallon piece.

I was drawn to this one as I didn’t have a lot of overhead space on which to hang it and it seemed like a solid deal for the output it was offering.

The spectrum seems to be spot on for what my Chaeto wants.

The blue-red combo on this one really set off its growth cycle and I, like my friend from before, was dealing with more Chaeto than I knew what to do with.

As far as a nano light for a refugium tanks goes I really couldn’t ask for more.

It’s pretty crazy what these small scale lights are capable of these days.

Plus there’s a long warranty on it, so if it goes out I can get a replacement.

Unfortunately, this one doesn’t have any timer or dimmer on it.

The fan is surprisingly quiet for its size.

I recommend the GrowStar UFO 150W for anyone on a budget that needs a small, but powerful LED sump light for their refugium.

I have seen this particular lamp being recommended left and right on reef keeping forums when it comes to cheaper refugium lights.

It’s honestly hard to find a bad experience with the GrowStar.

In fact, here is a macroalgae growth progression of 3 days achieved with the GrowStar UFO 150W:

By Dj City

 Advantages: 
  • Perfect spectrum with lots of proven success cases
  • Great bang for your buck
  • Grows many kinds of macroalgae, including chaetomorpha
  • Surprisingly strong for its size
  • Quiet fans that keep the lamp cool
  • Can be set on a timer
  • Spectacular performance in small to medium-sized refugiums
  • CREE LED chips (higher quality generation)
  • 2 years warranty
 Disadvantages: 
  • No dimmer / intensity control
  • Not waterproof
  • Longevity issues may or may not occur (though the warranty covers it, which is cool)

4. Kessil H80 Tuna Flora Refugium LED – Premium results in nano refugiums


Click here to see the current price + more photos on Amazon.

Kessil is a brand with an established reputation in the world of reef keeping and if you’ve had a saltwater aquarium before you’re probably familiar with their (well deserved) fame.

The Kessil H80 is an excellent choice for anyone looking for an LED light system made specifically for sumps and refugiums.

There’s definitely plenty to like here. Marketed for refugiums, it obviously works equally well as a sump light.

The LED they use is low-wattage, but that’s because the light it’s producing is just in the range for aquatic plants.

Meaning there’s less wasted light that’s not really useful for your Chaeto or coming off your sump.

There’s also a nice control system on the main body of the light that allows you to fine-tune things for your specific needs.

All of this is good, and from what I’ve seen from it the light does its job and it does it well.

The spectral quality is proven to work, not just by us reefers, but also by the Kessil research team.

See, these guys are in the LED lighting industry long before many of the brands listed here.

They have their own research facilities and take the quality of their products very seriously.

Nailing the right spectrum and PAR intensity are two things you don’t have to worry about if you’re going for a Kessil.

The only issues I’ve seen are that sometimes there’s a dud in the batch.

Not exactly sure where the issue lies, and the company is good with returns, but it’s a potential issue.

Another thing that some may consider an issue is pricing.

On top of being a little pricier than most models listed here, you’ll also need to buy the Spectral Kessil controller separately if you’d like to take full advantage of this light’s customization potential.

Aside from that weird business decision, the pricing of the fixture itself is fair as this is premium refugium lighting with durable components and high quality LED chips.

With that aside, this is a great light that doesn’t create excess heat or waste energy made specifically for refugium and sump tanks.

It’s good stuff, and the product is an amazing concept and one of the best out there.

I recommend buying the Kessil H80 if you have a more loose budget for equipping your small refugium with a durable and efficient LED light.

Your Chaeto will thank you by destroying any traces of excess nitrates and phosphates.

Set the mode to “Grow” if you don’t want to play with the settings too much.

Here’s a hefty ball of Chaeto grown under a Kessil H80:

By reefbuilder

 Advantages: 
  • Durable with a quality build
  • Lab-researched spectrum for improved photosynthesis
  • Definitely grows Chaeto and really fast at that
  • Sleek look
  • Silent work
  • Fantastic cooling system
  • Is customizable and dimmable
  • Excellent as a small sump light
 Disadvantages: 
  • You need to get the Kessil Spectral controller separately to unlock its full customizable potential
  • You need to get the gooseneck separately for optimal flexibility when positioning

5. CF Grow 200 W – Flood-type LEDs for a massive yield


Click here to see the current price + more photos on Amazon.

Loudness. That’s an issue I ran into with a few of the popular grow lights, some of them were louder than my pumps.

Not with this fixture at least. Anyway, the light spectrum of the CF Grow 100W is good for macroalgae, especially Chaetomorpha.

The fixture comes in a compact size which saves space in the sump.

One of the best nano lights I’ve seen and at a budget price, which is the main reason it makes this list.

However, the size of the fixture itself should not mislead you.

The Chaeto in the refugium we tried this on grew like crazy and we’d have to harvest it every 2 weeks or it would literally creep out of the sump.

This fixture uses COB LEDs and it is designed as a floodlight as opposed to spotlights.

This means way better spread, making it ideal for massive refugiums as long as you position it at least 12” from the surface.

There’s a couple of things to be aware of with this light, however.

The trade-off for the low price point is the lack of any true control, and the trade-off for the low noise level is there can be heating issues with this light if you don’t give it enough headroom.

I made this mistake initially, putting it on a compact refugium with very little shelf space above it.

It got a bit hotter than I expected.

Being waterproof helps with prolonging the life of the product by a significant margin, as long as there’s a heat sink of some sort in your cabinet.

But if you keep that in mind you’re looking at a really solid nano LED light for a sump setup and a really good price point.

I recommend this LED light for those of you who have a tighter budget but want to achieve excellent Chaeto growth in their large refugium.

Just make sure that the produced warmth goes somewhere and does not circulate inside your sump’s cabinet.

Here’s what the 200W CF Grow is capable of over a large refugium:

By wangspeed

Note that the user from the photo did install a couple of heatsinks on the fixture but claims that it may have been unnecessary.

 Advantages: 
  • Budget-friendly given what you get in return
  • COB LED flood-type of light, which means enormous spread
  • An adequate choice for large refugiums on a budget
  • Operates silently because there are no fans running
  • Can be set on a timer
  • WATERPROOF
  • Spectral quality is top-notch
 Disadvantages: 
  • Gets rather warm (you could plug a couple of heatsinks on it, though manufacturers claim that it’s normal)
  • Not dimmable

6. TaoTronics LED Grow Light Bulb – Best PAR per dollar ratio


Click here to see the current price + more photos on Amazon.

In my quest to switch over my refugiums and sumps over to LED lights, I ran into a bit of a wall when dealing with smaller tank setups.

This wasn’t really an issue until the light of my friend’s sump went out.

Smaller refugiums usually means smaller sump cabinets, which if not ventilated well may generate some heat and affect the temperature in the display tank.

So now I was looking at another good bulb that would grow Chaetomorpha without question but also produces very little heat.

Luckily, I stumbled onto this.

These are multiple LEDs made into bulb form that can be socketed into whatever hood you have already.

They’re technically an advancement of the PAR38 technology in LEDs that dissipate heat better, but it’s a similar concept.

This makes them an ideal replacement for those that already have a grow light, but want to make the swap to LED lighting.

The light spectrum is perfect for macroalgae and the penetration is great due to the PAR38 bulb being quite intense.

I’ve seen the “green” version put at work, but when we were doing the shopping research there were plenty of reviews and reports of the red one being as effective for refugiums.

The difference between the two is that the green TaoTronics has 2 blue diodes, where the “red” one is all red ones.

This makes sense in terms of achieving explosive growth as seen in the scientific proof that Michigan State University provided when researching the photosynthetic spectrum.

On a side note, I wasn’t really able to find someone complaining that this bulb does not grow Chaeto well.

What further pushed us towards the purchase was a decent amount of forum users providing their positive feedback as well.

It’s a cost-oriented LED light that works absolute wonders in refugiums.

Furthermore, it runs cool and quiet.

The only issue is the lack of any specific light system designed to get the most out of them, though they socket into just about anything.

Lights like this are, for sure, the future of indoor and aquatic growing.

I just wish there were more hoods designed with them in mind.

You should know that if your fuge is larger than, say, 20 gallons you may need to get 2 units.

It’d be best to buy the Taotronics for your refugium if you have a smaller sump cabinet that’s not well ventilated.

It is also really good for people that have high-end aquarium lighting over their display tanks as this bulb reportedly produces 1200+ PAR 15” off the light.

This means it will easily compete with the display tank lighting and forcing the algae to grow in the refugium and not the main aquarium.

This setup remains cost-efficient even for larger refugiums that would require more than one bulb for full coverage.

Here’s a real case of what you can expect when installing a TaoTronics grow light over your sump:

By moab361

And here’s a Chaeto growth progression of just 4 days over another tank:

By MichaelM123

And a final shot of a PAR measurement reading 1500 micromoles just 15 inches below the LED bulb:

By MichaelM123

 Advantages: 
  • Very inexpensive
  • Astonishing intensity for the price
  • Fantastic heat dissipation
  • Light spectrum obviously shows massive results
  • PAR38 technology (less heat, more intense, less energy consumption)
  • Pretty energy efficient given how intense it is
  • Grows Chaeto and other macroalgae like crazy
 Disadvantages: 
  • Not waterproof (install above a glass top to extend its life)
  • Not dimmable

7. Kessil H380 Spectral Halo II – Optimal for Display Tanks with High-end Lighting


Click here to see the current price + more photos on Amazon.

Now, this is a light.

The Kessil H380 Spectral Halo II is, in my opinion, one of, if not, the best choice for an LED refugium light to use over your sump.

When I powered this on I was really surprised by how little light was spilling over and wasting my electricity.

There’s something about the lens they use that aims the light exactly where you need it to go and nowhere else.

This means that you need less wattage than other products, but the Kessil is still a powerhouse when you need it to be.

The max setting on this light surprised me.

I had it going on my 26-gallon sump, and I realized very quickly that I am going to have to move it up.

This is a good thing, it’s really bright.

Mind that you may “burn” your Chaetomorpha if you position the fixture too low.

A sign of that would be the plant turning white. Place it 12 to 15” above the refugium if possible.

Another thing I need to discuss is that the spectrum range of the diodes seems to be spot on (as expected from a Kessil).

This light works really well for growing Chaeto.

I was having to manicure my macroalgae back after the first week or so and I was actually astounded at how fast they were capable of growing under these conditions.

A baseball-sized ball would turn into a basketball-sized one in just over a week.

Nitrates and phosphates – undetectable.

I’ve had more success with the “purple mode”, but you can experiment with the “magenta” one as well.

The only issues here are the price point, it’s one of the more expensive lights on this list, and the lack of a timer.

You’ll need to get the separate Spectral controller to take full advantage of the customization.

The light is adjustable, but for some reason, they didn’t include an automatic timer in the design.

I don’t really see why this is, it’s not that big of a deal either way for me, but for some, it could be a deal-breaker.

For me, I had other coral aquariums that were using Kessil lights at the time so I already had the controller.

If you’re a hands-on macroalgae farmer and price isn’t a factor, then this is a great grow LED light for a thriving saltwater refugium.

Buy the Kessil H380 Spectral Halo II if you want a very durable and intense grow light that will be able to outcompete the high-end reef lighting you have in your display tank.

Here’s a little over a month worth of Chaetomorpha density and growth with the Kessil H380:

By magnetar68

And here’s a nice refugium chamber of a sump that houses gallons of Chaeto grown with a Kessil H380:

By BeanMachine

 Advantages: 
  • Very intense and powerful
  • Extremely long-lasting
  • Lab-researched spectral quality
  • Stylish design
  • Top-notch ventilation system that runs silently
  • Grows Chaeto almost too fast
  • Pre-set spectrum modes that work, but can be customized further
 Disadvantages: 
  • Not waterproof
  • Not dimmable
  • You need to buy the Kessil Spectral Controller separately if you’d like to tweak the spectrum (not necessary, really, the Kessil does its job anyway)

Should You Get a Cheap One Over the More Expensive Premium Products?

This is a frequent question that gets asked and is one I had myself when I was first starting.

I try to keep budgetary concerns in mind when I write these out, as I know we can’t all spend a whole lot on tank accessories.

Still, it’s important to make sure you’re doing the best you can afford for your plants so let’s take a look at the pros and cons of a cheap refugium light:

A cheap refugium light will indeed get the job done. As long as the light it produces is in a good spectrum for your plants, and there’s enough of it, macroalgae such as Chaetomorpha will grow. What you will miss out on when going for the cheaper option, however, is certain things like light settings and customization options.

These aren’t that important if you’re a hands-on refugium owner, but you also may take a hit on longevity and light waste.

Certain cheap lights may have a high total wattage, but a lot of that power gets spread out and dissipates deeper in the tank.

This, however, is not a rule. Most of them I’ve listed here, even the budget ones, don’t have this issue because they use newer energy-efficient light diodes.

In fact, a couple of the best I’ve tried are what many consider inexpensive options.

Do a bit of research on what’s best for your budget and check out what I’ve listed here, fitting in your pockets doesn’t mean you have to take a hit on light quality.

Recommended Schedule and Daily Photoperiod

There’s a bit of debate on the web about the optimal light schedule for Chaeto and other macroalgae, and I’m of the opinion a decent amount of it is misinformation and misunderstandings on how the plants operate.

Here’s a universally recommended schedule for a refugium light:

Aiming for a timing similar to natural photoperiods is the ideal way to set your refugium light schedule. This means something along the lines of 12 hours on, 12 hours off is generally considered the best.

Some people leave their lights on for 24 hours, but there’s not really any evidence to support this and it may actually stress out the plants, causing photoinhibition (slowed or stunted growth).

At the same time, anything less than 12 might not give your macroalgae enough to produce important nutrients for itself.

Depending on the light you have, you can experiment with the schedule somewhat.

There’s a sweet spot somewhere between more than 12 hours and less than 18 hours, and a bit of trial and error should get you there.

Additional Tips for a Thriving Reef Tank

Aside from a well-maintained refugium, there are other things that can be done to ensure proper filtration in your saltwater reef tank.

Some people swear by refugiums with blooming Chaeto as their sole form of aquarium filtration.

Yet every tank is different and in some cases, this may not be enough to lower your nitrates down to the desirable level.

If you’re still worried about water clarity you should take a look into the best GFO or carbon media reactor units.

These will help tremendously with phosphate levels, which can quickly become an issue in overstocked or large reef aquariums.

They’re pretty simple, but somewhat underrated filter chambers, that house a specific media and are excellent in these situations.

Another issue that may crop up is the growth of additional hair algae that you’re not targeting.

This can be a problem with water balance, such as overnutrification, but can also simply be a consequence of too much of the wrong light spectrum in your display tank.

To learn more about what spectrum to use for coral growth and which fixtures support it you can check my article on the best LED reef lights.

Chaeto mostly absorbs red and blue light, but the requirements for your display tank LEDs are different.

No one likes to feed unintended hair algae blooms in their saltwater aquarium.

Conclusion

I remember just a few years ago, most people didn’t recommend LED lighting for growing plants.

Now, they’ve gone from relatively niche products into the go-to for plant growth, especially in sumps and refugiums.

I love watching the tech growing like this, and I’m completely convinced LED lights over refugium tanks are now the best for a giant Chaetomorpha yield.

I hope this helped, and Aquanswered all your questions, but do drop me a comment if you need some more guidance.

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