Other half of mixed reef tankReal Clear Results with Nualgi AquariumsMore increased Coral growth from Jorge's tankTestimonial from Fresh & Saltwater Aquarium Owner Christian D.Matthew W. Test in Planted tank, Shrimp tank & Aggressive TankPlanted freshwater tank trialing Nualgi Aquarium

Nualgi Aquarium

4.87 out of 5 based on 46 customer ratings
(46 customer reviews)


Engineered specifically to benefit the health of your fish and coral, Nualgi Aquarium is easy to use, efficient, and yields rapid results. Supercharge your tank’s nitrogen cycle and give your bio-filter a boost — try it today!

SKU: nualgi Category:
DID YOU KNOW? According to a 2015 study by the scientists at the National Marine Aquarium, watching an aquarium can lower your heart rate, help reduce high blood pressure, and improve your mood.

Product Description

We all know there is no such thing as a silver bullet for maintaining a healthy aquarium… but we have engineered an innovative water treatment for aquariums which will supercharge your tank’s nitrogen cycle and make your bio-filter more efficient. The result: Crystal clear water with increased oxygen levels and healthier plants, coral, fish, and crustaceans. Try it and see for yourself!

Shelf life of 3 years – Stock up for next year too!

Bottle Size Recommended Tank Size Cost for Full 8 Week Cycle of Nualgi
Fresh Salt Fresh Salt
4oz     15 – 60 Gal      20 – 85 Gal $14.99 / 60 Gal $14.99 / 85 Gal
16oz  60 – 240 Gal     85 – 340 Gal $39.99 / 240 Gal $39.99 / 340 Gal

When You Supplement Your Routine With Nualgi, You Will…

  • SEE MORE –  Reducing nuisance algae growth on glass and in your tank, Nualgi improves water clarity and visibility to reveal more of the tank’s environment and its inhabitants.
  • FEED LESS – By restoring missing nutrients, Nualgi brings balance to the natural marine food chain from the bottom up by promoting the growth of diatoms and zooplakton – free food for your fish and corals!
  • CLEAN LESS – Nualgi controls and prevents the growth of nuisance algae as diatoms produced by Nualgi out-compete bad algae for nutrients and increasing dissolved oxygen (DO) levels, improving water quality  –  fewer water changes!
  • WATCH YOUR TANK FLOURISH – Nualgi Aquarium will significantly improve your coral and fish health and longevity, and our trials have shown Nualgi Aquarium can kick start new coral growth in as little as 1 week!

Additional Information

Weight 3 oz
Dimensions 6 x 3 x 9 in
Tank Type

Freshwater, Saltwater

Bottle Size

1oz, 4oz, 16oz

46 reviews for Nualgi Aquarium

  1. 5 out of 5

    (verified owner):

    What an amazing product! And all natural too! I run a high tech planted discus tank, And without Nualgi I know I’d be fighting a daily battle with algae. Keeps the water crystal clear and enhances plant growth. Fish are happy and healthy.

  2. 5 out of 5


    Superb product! I was very hesitant to add anything other than essential amino acids and vitamins to my reef tank for coral growth. This product has quite simply replaced those for me. All the growth, and immediate polyp extension I used to see with my “coral food”, while actually deterring algae instead feeding it like most other products.

  3. 5 out of 5


    This stuff works amazingly well! It was even able to overcome Green Water w/o altering the photo period of my planted tank! Now the water I drain is as crystal clear as the clean water I use to fill with during water changes.

  4. 4 out of 5


    As far as food for coral this product is hands down the best. I had more growth in the 12 weeks of using their product than ever before.

  5. 5 out of 5


    An excellent product! I’ve seen a vast difference in my reef tank since I started using Nualgi. Even my friends have passed comment on it. The water is clearer, the rocks and sand appear cleaner, the corals are more inflated and showing better polyp extension. I’ll continue to use it after my trial ends.

  6. 5 out of 5

    (verified owner):

    Jason Guardado

    Since week two of dosing I was a believer. I had green hair and cyano in my 120g mixed reef but not for long. Nualgi took no time to kill the nuisance algae. Since then I have continued to use it and I have had rapid growth with all my Zoas, SPS, LPS and my fish look healthy as ever. Thanks Nualgi for a great product.

  7. 5 out of 5

    (verified owner):

    I was skeptical that Nualgia would achieve all it claimed and was super excited when my algae started disappearing! In my 12 week trial it eliminated all the algae I had been battling for months. I highly recommend this product for anyone looking to rid their tank of all types of nuisance algae in one simple step!

  8. 5 out of 5


    The Nualgi worked amazingly. I have a planted Discus tanks with swords and it was refreshing to not have to dose the multiple bottles I usually have to dose. Would recommend this to anybody who asked, even recommended it to the owner of the pet store I work for.

  9. 5 out of 5


    I’ve already ordered and received the large bottle and I’m very happy with the results. I have a 260 gallon reef tank and the nualgi has made my water clearer and got rid of my algae. So let me say thanks a lot and let you know I tell everyone what a great product you have.

  10. 5 out of 5


    Fantastic product! Water changes and tank cleaning went from 2 weeks to 6 weeks. Corals and fish immediately perked up and became more active!

  11. 5 out of 5

    (verified owner):

    I will not go without it ever! It’s magical!

  12. 4 out of 5


    This product is pretty amazing. It works great with all my corals, hard or soft.

  13. 5 out of 5


    I noticed that my coral was growing and the whole tank looked better than it had before. So pleased I ordered another bottle.

  14. 4 out of 5


    Initially great reaction from corals. Tried dosing weekly and daily. Got a bit of green algae on the rocks so lessened the dose which sorted that. I will continue to use dose twice a week.

  15. 5 out of 5


    I’m not normally compelled to review a product, but this Nualgi stuff really surprised me. I bought the trial bottle a few months ago, at the time my tank was looking a little rough; I had cyano, a couple of rocks with a bit of hair or turf algae on them and I was cleaning my glass every day or 2. I filter my tank exclusively by Algae scrubber and have always been relatively happy with the results, I wanted to see if this product would complement or compete with my scrubber. The price was right so I figured why not give it a try.

    When the product arrived I read their recommendations which included reducing the tank temps, and shortening the photo period. At this point I figured the product was Bull$hit, and I probably just bought a bottle of distilled water or something.

    I dosed my tank per the instructions ( I did nothing to my tank with regards to light schedule or temp) and started to get a diatom bloom, I then started dosing 1/2 of what they recommend also per the instructions. To my surprise my algae screen growth exploded, the mass of algae that always grew on top of my powerheads and locline started to disappear, the slime went away and the diatoms cleared up.
    This happened over a time period of about 6-8 weeks.

    When I bought this stuff, I was incredibly skeptical. I only bought it to support a new sponsor who was offering a good discount, I never really expected it to work, but I’ll be damned if it didn’t.

    During this time I siphoned nothing, and changed nothing with regards to flow, lighting or feeding. I am sure the cyano would have cleared itself up by now without the Nualgi, but the pockets of algae that grew on my overflows and powerheads have been an issue since I set my tank up a few years ago and for the first time I am not cleaning them every couple of weeks. I’ve only been cleaning the glass about 1x per week for the last month as well. Sure I still have some algae but all in all, I am of the opinion that this stuff works.

  16. 5 out of 5


    Worked well. Faster than normal growth and corals looked fantastic.

  17. 5 out of 5

    (verified owner):

    I love the product but it gets expensive with a 180 gallon tank.

  18. 5 out of 5


    Great product.

  19. 5 out of 5


    First of all, this review applies only to my densely planted tank, not to a salt tank or a bare glass tank. While the product does NOT eliminate all algae (in particular, you might need American flagfish to handle small amounts of surviving hair algae), I still decided to give it 5 stars because it’s the best product on the market for the purpose, without being expensive to maintain like a UV sterilizer or poisonous like algicide. Definitely, for best results, use an ammonia remover in if your tap water contains ammonia as part of chloramine treatment, because excess ammonia following a water change will enrich algae. I used 1.5 mL of this stuff every 4 days for 12 days in my 40-gallon tank, and it heavily suppressed my waterborne algae problem, which otherwise would have been obvious in less than a week. But the main reason for the 5-star rating was: After a week, I had a modest amount of hair algae on the glass, even though the tank was otherwise nearly clear. When I scraped it off into the water, the water of course immediately turned a tinge of green. But 2 days later, it was back to being nearly clear. The only weird effect has been the accumulation of small greenish dots on the water surface. I don’t know what these are, but they seem to be harmless and in any event occupy only a small fraction of the surface. It seems like nonsense that only 1.5 mL of this stuff every 4 (or up to 7) days can achieve such effects, but I have to admit that it worked in my case. The reduced time and water waste is well worth the price. (After 12 days, my tank looks like it usually does on day 2 or 3.) My only complaint is that it seems to contain phosphorous, which is completely unnecessary because fish food and tap water and generally loaded with it to begin with.

  20. 5 out of 5

    (verified owner):

    The stuff works great! I used it in my saltwater tank and I haven’t had an ALC since I started using it or any serious Elsie.

  21. 5 out of 5


    We’ve been using Nualgi for around a year now or close to it and have wonderful fullness and growth with all our corals. I would highly recommend it.

  22. 5 out of 5


    Nualgi exceeded my expectation by far! Since I started with the product, I saw instant result. I wasn’t scrubbing the glass everyday, all my polyps came out to play 🙂 all my fish looks healthier . Had a frogspawn coral I left there to see if it bounces back and it sure did! Overall this product works wonders! I’m only 3 weeks into dosing the product with a lot of positive signs 🙂

  23. 5 out of 5


    Nualgi is an awesome product, one that does everything it claims and does it very well! I’ve been using Nualgi for over a year, and, I’ll never go without it in my fish room!

  24. 5 out of 5


    Nualgi is an excellent alternative to many forms of algae control on the market today. In an era of exploding information in this hobby I have found Nualgi to be a very useful tool in controlling nuisance algae in both marine and freshwater aquariums with a relatively good rate of success. Also, the support by the company is outstanding. Definitely worth a try.

  25. 5 out of 5


    For over a year I’ve been battling a hair algae breakout. I did a trial of this product about a year ago and had minimal results. Nothing bad happened, but it didn’t seem to do much.

    This fall I participated in an experiment where Nualgi was combined with Microbelift Aquarium Balance or TLC Smart Start (in both cases, weekly maintenance level doses alongside the standard Nualgi dose). These are both bacteria products, and I’ve tried to break the algae infestation with bacteria alone with similar results to Nualgi alone – some improvement, but no victory.

    However, this combined approach is quite potent. The tank glass stays clean all week, growth of hair algae stops, and I was finally able to break the cycle of hair algae. I even had a sunset montipora come back from the dead (was exciting to see a couple polyps appear, then a few more, then colors, and now it’s growing again).

    My tank is a mixed reef with a few soft corals, a few LPS, and a lot of SPS. The fish population includes a few tangs, which can be sensitive to water quality. The inverts include hermits, snails, conchs, and urchins. None of these creatures showed any signs of stress during treatment. The corals are all flourishing and exhibiting strong growth.

  26. 5 out of 5


    Great product and company. I have two 65 gallon reef systems. I had a hair algae problem and, after trying other methods, decided to try Nualgi last spring. The first thing I noticed after dosing was the amazing growth of my corals. I never imagined that they could grow that fast and colorful. This alone is reason to use Nualgi. My hair algae issues however, continued. Nualgi suggested that I should add additional silica to my system, which I did in addition to weekly dose of Nualgi. This, over a period of time took care of the problem and I was able to discontinue the additional Silica. Since then there has been no Hair algae in my tank. My glass is cleaner than ever with only the weekly dosing of Nualgi.
    A few months ago I noticed some Cyno in one of the tanks. When the people at Nualgi suggested that add some SmartSmart Complete to my weekly Nualgi the red Cyno quickly disappeared.
    Now I have crystal clear water, no algae in tanks and coral growth and fish that are beautiful. I couldn’t ask for more and the dose of Nualgi is an important part of my weekly maintenance.

  27. 5 out of 5


    Interesting product, quick delivery, clear instructions. I’ll post an update when I see how it works.

  28. 2 out of 5


    They are in caadna and dont ship out of caadna. So if your in the states, dont bother. Send them an email or call them. Its acrylic, not glass. My site has calculators to find thickness.

  29. 5 out of 5


    I’ve had the pleasure with Nualgi and their products for a year now and have been impressed. Nualgi Aquarium and Nualgi Pond flat work. I been keeping fish inside and outside for almost 20 years. All fish keepers have their special quirks, Nualgi is mine!! The last ten of my professional life is keeping antibiotic and chemical use down in all kinds of production animals, so finding a product that WORKS the same way in my aquarium and pond is a wonderful find. All we can ask from a (any) product is that it works at the level instructed and all the time. I urge all keepers of any type of aquarium or pond to use this product with the right type of microbial product together for a month and you’ll know why I won’t keep fish without it.

  30. 5 out of 5


    Great Product

  31. 5 out of 5


    I was algae free for months and I ran out of Nualgi. The result was a large amount of algae growth. I started dosing again and after about 12 weeks I’m algae free again

  32. 5 out of 5


    Good stuff

  33. 5 out of 5


    I am entirely satisfied with the product. I will order Nualgi in the future, and recommend to others

  34. 5 out of 5


    Work great so far

  35. 5 out of 5


    Did exactly what it said it would. Was having an issue with red algae and after 2 treatments algae was controlled. Fish are happy and tank looks great

  36. 5 out of 5


    Thank you

  37. 5 out of 5


    Excellent product. Will use this on all my aquariums.

  38. 5 out of 5


    Nualgi is not for bacteria, Nualgi helps Balance the nutrients in your aquarium so you don’t have to deal with algae problems. If you’re having a bacteria problem you need to take a different approach as bacteria blooms are triggered by poor husbandry, low flow and lighting to name a few. If battling bacteria bloom try redirecting flow to it, that spot where is growing may not have enough flow and lighting may be poor. If using florescent lights change the bulbs as too much red spectrum will trigger bacteria and algae blooms. The product really works but if you have your equipment running poorly then don’t expect a product to work effectively

  39. 5 out of 5


    Product seems to be hard at work on algae. I have been struggling to control. I had gone with no lights and that wasn’t doing the trick. This product is easy to use, and was a great find.

  40. 5 out of 5


    Water quality improving in 120 gallon reef tank

  41. 5 out of 5


    Like others we have been struggling with the ever present algae problems for years, tried everything and have spent a tremendous amount of time and money trying to control it in our beautiful Koi pond.
    I was very skeptical about product claims and what harm could come to our Koi’s.

    After just a few applications in a very dark green algae infested water, we noticed an improvement in the reduction of algae. After just a month the water became clear and the edges of the pond you could see the algae being removed.
    After several months now with just a few addition of this product “NO MORE ALGAE”
    Thank you

  42. 5 out of 5


    See any algae? Of course not, Nualgi works awesome. It’s amazing. I used to have algae all over my plants the gravel the glass it was terrible. And then I tried Nualgi

  43. 5 out of 5


    Your product works awesome. I use it and never had an algae problem.

  44. 5 out of 5


    Product works great for me by the way

  45. 5 out of 5


    This product surprised me at how quickly it began working. My 55 gallon freshwater tropical aquarium has timed LED lights that are great for plant growth. But a side effect that’s common w/ the LED’s is massive growth of hair algae. It’s nasty stuff to look at covering attractive rock, wood and gravel features. It also gets all over your plants. I used this stuff about 2 weeks ago according to the directions. A week went by and I daily thought my eyes were playing tricks on me. Now I’m convinced it works. There is now far less hair algae on the rocks. In this 2 year old tank the colors on the rocks are again visible, in some areas the algae is nearly gone! On the wood the algae is now much smaller. None of my fish eat that algae so I don’t know what’s eating it, perhaps the diatoms as the description claims. In addition the fish remain healthy and in good color. Being that it’s only been 2 weeks we’ll see how it continues over time but so far it’s incredible.

  46. 5 out of 5


    I have a Cichlid aquarium with 2 Plecos. I began having trouble with algae even though I cleaned the tank, did water changes, and treated the water as recommended. I stumbled on Nualgi and thought I’d give it a try. My tank is now crystal clear and has never looked so good. My fish also look happy – they swim more and are more active. I will purchase this product again and will use it each time I do a water change.

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ATTENTION SHOPPERS, Prices on all sizes of Nualgi increased on January 1, 2021.