The Best (And Worst) Planted Tank Aquarium Lights
Updated 8/16/2024 with new recommendations and information.
Not all lights are created equal. And, unfortunately, it’s often the downfall of the planted tank world. Much like how aquarium filter manufacturers sell you cartridges that actually make your tank worse (They do! Just use a sponge!), LOTS of light manufacturers will pump your head full of an unbelievable amount of misinformation that just results in bad looking aquariums and sad plants after the customer pays way too much.
I put together this comparison to explain my experience with aquarium lights, and to explain why many lights people often consider “high end” are actually some of the worst lights you can get for your tank. This guide focuses entirely on LED lighting, and I do not recommend using fluorescent lights.
And, for the record, investing in ANY sort of plant light is infinitely better than just using the hood on your aquarium. This guide doesn’t even factor that in, and you can usually safely assume the small LED strips included in aquarium hoods won’t do a good job at growing plants at all, and will make your fish and decor look dull and drab. Toss the hood for a glass lid, or affix a light underneath the hood with some superglue!
Product recommendations and tl;dr summary at the bottom of this article.
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What about algae?
Algae grows because of an imbalance in an ecosystem, not because of too much light. Upgrading your light can cause a temporary imbalance and algae explosion, but your tank will adapt and balance it’s ecosystem to the new light and eventually become fully stable with the stronger light. Just stay on top of water changes in the meantime.
And in fact, more light generally makes tanks MORE resilient to algae, because your plants will be healthier and healthier plants repel algae.
What about my fish?
Despite what some people might believe, there is nearly no negative correlation between light brightness and fish health. Fish are used to existing in direct sunlight, so a bright light is no issue for them, and in fact the healthier plants will promote better water quality for them. The only lighting factor that impacts fish is the duration of lighting, which generally doesn’t make a big impact but can impact breeding and growth in some species like ricefish.
“I have a full spectrum Plant Light”
I hear this a lot. And it’s not a bad thing, by any means, but it also isn’t great. Many plant lights are advertised as Full Spectrum which lead people to think it’s the best for plants, but it isn’t.
But, before we compare lights, let’s explore the most important parts of lighting: Power and Spectrum.
Light Power
What factors should I care about?
Lumens? Watts? PAR? Amount of LEDs? What factors actually matter when shopping for a light?
In short, almost all of them, but you truly only need to worry about wattage as, in general, higher wattage = more power.
HOWEVER, the other factors do matter too.
Lumens is the raw brightness output of a light- this doesn’t necessarily correspond to how strong the light is or how well it will penetrate the water, but generally you can also assume that higher lumen lights are more powerful than lower lumen lights.
Watts is the actual amount of power used and outputted by the diodes of the light. Lights can have a higher lumen output without using as much wattage, but in that case they won’t be as good at penetrating water. Higher wattage basically means a higher output and thus a brighter, stronger, more effective light.
PAR is, in most cases, not needed when shopping for a light. It IS important when it comes to fine-tuning very high end setups, but for most cases when shopping for a light you can pretty confidently ignore PAR values in favor of wattage. The exact amount of light that hits the substrate depends on tons of factors including your water parameters, substrate color, light height, etc and it generally won’t ever be totally accurate, and in general a high wattage light will work great for what you need anyway. You can also safely assume that in most cases, a light with higher wattage will have better PAR.
Those are the only 3 factors that really matter in terms of light output. Amount of LEDs, CRI, brightness levels, etc don’t really matter at all. But remember that the spectrum matters just as much if not more (explained below).
How much wattage do you need?
Light power is measured in wattage, which determines how bright and strong the light will be. Lumens aren’t always a great measurement of a light’s quality as one should consider PAR, which is a measurement of light at the bottom of your tank. With this note, also remember taller tanks need more powerful lights so the light can penetrate deeper.
The 1-to-1 rule for a decent light
The 1-to-1 rule says that for a “decent” light, get something with a wattage roughly equal to the gallons of your aquarium. For example, a 40 gallon aquarium should have roughly a 40 watt light.
This is for what I would consider the bare minimum for a “decent” light for a planted aquarium. A light this powerful will be strong enough to grow most easy to medium plants and generally set you up for success for a planted aquarium. A light much weaker than this may result in unhealthy or dying plants, especially in taller tanks.
Again, remember that if you have a really deep tank, you should consider even higher wattage so the light can get all the way to the bottom. I’d say anything 16” or taller would count as “deep”.
The 1-to-2 rule for a good light
The 1-to-2 rule says that for a truly GOOD light, shoot for a light with a wattage at least twice the gallons of your aquarium. A 20 gallon aquarium should have a 40w light, a 55 gallon aquarium should shoot for at least 110w of lighting. This is also a total, so two 20w lights roughly equate to a 40w light.
Note that this is for what one could consider HIGH tech (assuming the spectrum is also good). Lights this powerful can generally grow almost any plants in the hobby and will allow you to grow dense carpets and make your fish pop with color.
Marggoo, RGB Spectrum, 12W, 10gal
Light is also elevated a little bit compared to the other light, but notice how much darker the substrate is.
Sea Lantern, RGB Spectrum, 18W, 10gal
The Sea Lantern has superior PAR to the light above, and it’s also considerably brighter and lights up the substrate and plants noticeably more. Notice how the colors pop far more as well.
UPDATE NOTE: We sell a different version of the Sea Lantern now, which is even cheaper but still just as great! Check out our Equipment Shop.
Light Spectrum
Light spectrum is arguably more important than wattage. So let’s get this out of the way first: Full spectrum lights are not ideal for plants. Let’s explore why.
Red and Blue make plants grow
In fact, only a few very specific wavelengths actually help grow plants, which is essentially bright blue and bright red. Despite what any other ads might say, plants really only need these wavelengths. And, more importantly, any light that isn’t important to the plants just means you’re adding extra light that algae can use to grow.
Red light primarily is used to encourage coloration in plants. Add more red light to your spectrum to make your plants grow more colorful, vibrant, and rich.
Blue light is primarily used for growth. Add more blue light to make your plants grow faster.
Image/Data Source: 2hr Aquarist
The Magic Spectrum
Since you only need those two specific wavelengths around 480nm and 680nm or so, you can ideally cut out all other light which will both help prevent excess light and therefore algae, and it’ll help highlight those specific colors in your tank.
However, as we all learned in preschool, red and blue do not make beautiful colors in an aquarium, they make purple. So the solution is to also provide green light to balance out the red and blue and turn it into ‘white’ light. Remember that green light is effectively useless in most cases for growing plants in your aquarium, but it’s crucial for making your green plants ‘pop’ and look vibrant.
With these three colors focused on specific wavelengths, you get a lot more of a highlight and glow effect. With this, fish will be FAR more vibrant and you’ll see the colors shimmer in their scales as they catch the light. Green plants will light up vibrant and gorgeous, and red and purple plants will pop in striking colors.
You’ll also see dramatically improved growth with improved lighting.
The biggest realization for planted aquariums I ever made was when my plants grew awful after adding CO2, but grew incredibly after getting my first RGB light.
So, if you’re following along, you shouldn’t be surprised to see that “The Magic Spectrum” - The ideal spectrum for the perfect aquarium light, looks like this:
Week Aqua L Series Light Spectrum
That’s what you want to shoot for. Simply buying a light with a spectrum that looks like this will drastically improve your tank’s health in general and make your fish and plants appear so much more beautiful.
What spectrum to shop for
When shopping for a light, I don’t recommend even considering a light that doesn’t have the spectrum advertised, as you never know what you’re going to get. A light simply having red LEDs means almost nothing for the actual spectrum it outputs. Do your research and make sure you purchase a light with a decent spectrum and your plants and tank will thank you.
You want:
Lots of red and blue. Most lights have a decent bit of blue, but not many have lots of red. Look for both.
You don’t want:
Lots of light other than red, blue, and green. Like we mentioned above, plants can only really use strong blue and strong red light.
Any other light in the spectrum won’t be used by plants, so it will help algae grow.
(You may need to view this page in Desktop Mode on mobile to see the notes on each image)
I don’t Like Hygger or Nicrew, or most amazon lights.
There, I said it. I don’t. Hygger and Nicrew lights are the plague of Amazon lights and lead many users into believing they’re getting the best light for their tank with lots of fancy but unnecessary features, but they’re unfortunately wildly overpriced and often underperform.
Don’t get me wrong, these lights aren’t bad. By any means. They’re perfectly fine, they’re great for growing plants in low to medium tech tanks, and for a simple planted tank they’ll work perfectly if you already have one! However, if you’re shopping for new lights, it might be worth considering a different option.
But I Really don’t like fluval.
Fluval lights are without question the most overpriced lights on the market. If you have one, don’t fear! They’re still fine and still grow plants and all, but there are loads of better lights on the market for far cheaper. The good news is you can often resell them still for more than it’d cost to replace them with a better one!
One article exists online comparing the PAR values of a Hygger light vs a Fluval light, misleading customers into thinking a Hygger light will perform about as well as a $200 Fluval light. Which is true! It will! Except the fluval light also performs terribly, so neither of them are a good option at all, and if the article considered any other high end light both other options would look awful in comparison.
I won’t leave my distaste unjustified. Check out the below photos for a comparison of lots of different brands of lights. All photos were taken on the same phone at roughly the same angle on the same tank, and all were at max power with all lights on.
Other Plant Growth Factors
Obviously lighting isn’t the only factor that dictates how well your plants grow. In my experience, the most important factors that dictate plant growth, in order, are:
Lighting Power
Lighting Spectrum
CO2 Levels
Algae (Which is influenced by all the other factors)
Nutrients
O2 Levels
Substrate
You might notice that substrate is last- nutrient rich substrate like Fluval Stratum do help growth, but it isn’t nearly as important as lighting or other factors. You’ll also notice CO2 is underneath lighting, which I firmly stand by. Investing $100 in a good light will make a far bigger improvement than investing $100 in a CO2 system. Your plants will be much more colorful, your tank will look amazing, your fish will pop with color. CO2 is great in high tech tanks and a perfect complement to a good light, but a good light is more important.
CO2 and Algae do go hand-in-hand though, and increasing the CO2 levels in your aquarium will help reduce algae as well as improve your plant’s ability to grow and absorb nutrients. You don’t necessarily need CO2 injection for this though- increasing surface agitation and adding a surface skimmer both help dissolve more CO2 and O2 into your water. Note that liquid CO2 like Seachem Excel don’t actually add CO2, but they do help reduce algae.
As for fertilization, using any fertilizer with both Macronutrients and Micronutrients will do the job. Pet store fertilizers such as API and Seachem usually don’t include all nutrients necessary. We recommend our own Clean n’ Green for sale in our shop (which also includes growth boosters and algaecide!), NiloCG Thrive fertilizers, and 2hr Aquarist brand fertilizers.
Aquarium Light Comparison
Note: The gallery, and the notes on each photo, might not properly appear on mobile. Try switching to desktop view to read the description and title of each light.
Summary (TL;DR)
Shop for a light that is at least equal to the wattage of the gallons of your tank, for example a 10W light for a 10g tank.
For best results, get a light that has a wattage at least DOUBLE the gallons of your tank.
Lights with lots of blue and red in the spectrum are ideal.
Without lots of red in the spectrum, your plants won’t be colorful and red plants won’t grow well.
Product recommendations below include all my favorite lights from dirt cheap to super expensive
Lighting is more important for plant growth than ANY other factor, including CO2. A better light > CO2 System.
Stronger lighting doesn’t mean more algae, in fact it means less because your plants will grow healthier and absorb more nutrients.
We highly recommend AquaRocksColorado and AquaticMotiv as shops to find high quality lights.
We sell our own lights too! Check out our Equipment Shop for hand-picked recommendations and free shipping.
Product
Recommendations
I’ve personally tried almost every single one of these recommendations, and I’m happy to answer questions if you message us!
Prices are as of 8/2024 and for a 24” long (20 gallon High) tank unless otherwise noted.
When purchasing a light, get the biggest possible size for your tank. Don’t get an 18” light for a 24” tank. If the light is advertised as 24”-30”, the light itself is 24” long so you should get that for a 24” tank.
Good: LOW TECH LIGHTS
I don’t typically recommend low tech lights. Your light is the most important thing in your aquarium both for looks and plant health. It’s worth investing a bit more for a medium tech light if you can afford a bit more.
Sea Lantern. $22. BEST OPTION. Super cheap light that has shockingly decent output for next to nothing. Best budget light, hands down.
S3 Plus RGB. $20. Small, clamp-on light for nano tanks with great output for a great price.
LED Floodlights. $30 for 2. 5000K color temperature is ideal, don’t get ones too powerful. Great for big tanks.
RGB Smart Lightbulb. $17. Put it facing towards the tank in a flexible or hanging lamp and tune it to look good. Super cheap.
Better: MEDIUM TECH LIGHTS
One good Medium Tech light will dramatically outperform two or three Low Tech lights being used together.
Chihiros A II. $83. BEST OPTION. It’s the perfect medium tech light. Beautiful colors, great growth, great output, bluetooth control.
Chihiros A Series. $49. The A Series is incredibly strong for the price but it’s just white. Perfect for tall tanks.
Week Aqua Mini 9 Pro. $35. Perfect mini light for 5g or smaller tanks. Beautiful colors.
Week Aqua S Series. $75. Clips onto rimless tanks 18” or shorter (or rimmed tanks with some bending), perfect spectrum, arguably high tech. (Ships From China)
best: High Tech Lights
High tech lights are not only the best lights for plants and reducing algae, but will also make your fish and livestock appear extremely vibrant and beautiful.
You do not need CO2 to use a high tech light, but you do need a high tech light to benefit from using CO2.
Week Aqua L Series. $171. BEST OPTION. The perfect high tech light, outperforms WRGBII in my opinion for far cheaper.
LEDSTAR AQ-N. $86. The ultimate nano tank light. Gorgeous design and amazing output and color.
Week Aqua Z200 Pro. $230. Clips onto the back of any tank, and gives enough light for up to a 29g. I used two for a 60g. Amazing light.
Not Fluval.
Netlea AT5S. $159. Fantastic color rendering and plant growth with decent power for a great price.
Chihiros WRGBII. $320. Extremely expensive compared to Week Aqua, but it’s one of the best lights on the market.
Most Twinstar, ONF, etc other namebrand lights, but they’ll cost you way more and I personally prefer Week Aqua or Netlea over any of them.
Most high tech lights, especially the “Big Three” chinese brands Chihiros, Week Aqua, and LEDSTAR are primarily available on AliExpress. You can also get them at stores like AquaRocksColorado and AquaticMotiv, which we highly recommend and some of our links are affiliate links to their sites.
