API MARINE ALGAEFIX Algae Control 16-Ounce Bottle
Original price was: $26.48.$18.87Current price is: $18.87.
Price: $26.48 - $18.87
(as of Oct 19, 2025 19:14:46 UTC – Details)
API MARINE ALGAEFIX Algae Control effectively controls these types of algae: Green algae, “Red Slime”, and “Brown algae” in saltwater aquariums. Works fast. Will not harm marine fish, corals or other invertebrates when used as directed. With API Aquarium products, it’s easy to keep a beautiful saltwater, freshwater or reef aquarium. For over 50 years, API has been creating innovative, research-driven solutions that make it easier to care for your fish and aquarium. API Aquarium Treatment Supplies are designed to work in conjunction with each other to provide best results to control algae, promote healthy bacterial growth and help control and cure fish diseases and conditions such as ich and fin rot. They work to provide a safe, hospitable environment for fish such as tropical community fish, cichlids, goldfish and more. With API, you can spend more time admiring your fish, and less time scrubbing your tank. Make sure to use all products as directed in order to ensure the best results.
Is Discontinued By Manufacturer : No
Product Dimensions : 2 x 2 x 6 inches; 3.2 ounces
Item model number : 387D
Department : Unisex-Adult
Date First Available : June 24, 2004
Manufacturer : Mars Fishcare
ASIN : B0017JHBGY
Best Sellers Rank: #22,269 in Pet Supplies (See Top 100 in Pet Supplies) #194 in Aquarium Water Treatments
Customer Reviews: 4.3 4.3 out of 5 stars 2,167 ratings var dpAcrHasRegisteredArcLinkClickAction; P.when(‘A’, ‘ready’).execute(function(A) { if (dpAcrHasRegisteredArcLinkClickAction !== true) { dpAcrHasRegisteredArcLinkClickAction = true; A.declarative( ‘acrLink-click-metrics’, ‘click’, { “allowLinkDefault”: true }, function (event) { if (window.ue) { ue.count(“acrLinkClickCount”, (ue.count(“acrLinkClickCount”) || 0) + 1); } } ); } }); P.when(‘A’, ‘cf’).execute(function(A) { A.declarative(‘acrStarsLink-click-metrics’, ‘click’, { “allowLinkDefault” : true }, function(event){ if(window.ue) { ue.count(“acrStarsLinkWithPopoverClickCount”, (ue.count(“acrStarsLinkWithPopoverClickCount”) || 0) + 1); } }); });
Contains one (1) API MARINE ALGAEFIX Algae Control 16-Ounce Bottle
Controls algae growth and keeps marine and reef aquariums clean and clear
Effectively controls these types of saltwater algae: Green algae (Cladophora), “Red Slime” (Oscillatoria / Spirulina major), “Brown Algae” (Cyclotella) in marine aquariums containing live corals, invertebrates and fish.
When used in salt water will not harm snails, clams, scallops, shrimp, anemones, sea cucumbers, feather dusters, coralline algae, soft corals, hard corals and other invertebrates.
Dose every three days until algae is under control then dose weekly
Customers say
Customers find the algae control product effective at making water crystal clear and controlling algae growth, with one customer reporting complete clarity within three hours. The product receives positive feedback for its quality and effectiveness, though opinions are mixed regarding its impact on fish and safety, with some reporting fish deaths and toxicity concerns. While some customers consider it good value for money, others feel it’s not worth the cost.
12 reviews for API MARINE ALGAEFIX Algae Control 16-Ounce Bottle
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Original price was: $26.48.$18.87Current price is: $18.87.
GuitarGuyTim –
This stuff is a life (tank) saver!
I downsized from a 65g reef to a 28g cube last summer in preparation for a move. Because of everything going on, the tank was neglected. Within a month or so of neglect, some caulerpa macro algae had taken over the tank. It must have been a hitchhiker from the sump of my previous tank. I was literally filling up a 2 litter pitcher with algae every week as I was pulling it off of rocks and trying to get things under control. I was about ready to throw in the towel, boil all of my rock, and start over, but I decided to give AlgaeFix a chance.It took a few doses before I noticed anything, but probably late week 2, my skimmer started picking up a lot more “gunk” in the water. Over about a 2.5 month period, it has reduced the caulerpa by probably 90% and has it down to a manageable amount that I’m trying to eradicate through regular water changes and proper levels.AlgaeFix saved the life in my rock and saved me from giving up. I know a lot of people have asked if it will kill macro algae. I can confirm that the answer is yes, but it will take a long time before it wipes it out. I’m fully confident that you could clear up a hair algae breakout long before you decimate helpful algae in your sump.Great product that I will keep on hand for as long as I have reef tanks. Thanks!
Matt –
Works on bubble algae!
Had a small but growing infestation of bubble algae. Took a couple of months – but itâs all gone!! Now I just dose once per week to make sure it doesnât come back.
Hanning Group LLC –
Beware NOT SAFE WILL KILL YOUR FISH AND CORAL
NOT SAFE FOR CORAL. WILL NOT KILL HAIR ALAGE . WILL KILL YOUR FISH AND CORALDo not use this chemical NOT REEF SAFE!!! Killed all my corals in three days. YES I USED PROPER DOSE !!! Followed instructions on bottle to the letter. This did not help at all. DECIMATED MY AQUARIUM. IM DISTRAUGHT AT WHAT THIS HAS DONE. YEARS OF HARD WORK DESTROYED IN THREE DAYS.
Andruw91 –
Worked, but took a long time
I used this on my reef tank that had a huge green hair algae bloom out of no where. I read other reviews on this and was skeptical, but I wanted to do something to get rid of the hair algae besides removing all the rocks and scrub them. This is to be used once every 3 days until the algae is gone. At first it didn’t look like it was doing much, but after a week or some the green hair algae length began to shrink down. It took about 2-3 weeks for it to almost disappear, but it did work and I can see the surface of the rocks again. After reading people’s reviews on here it seemed that people were using this in fresh water tanks and it killed everything. A marine chemical shouldn’t be used in a fresh water tank. The dosing on my 55 gallon tank was just over a half of the cap every three days. Read the directions and get the right chemical for your tank. I would have given it 5 stars, but it does take a long time for it to work. Still beats scrubbing all the algae.
Amy –
Works well
Works well
Nikki –
Did not get rid of algae and lost almost all inverts in reef tank after 2 weeks of use.
*UPDATE UPDATE UPDATE*My apologies, after numerous tests we have discovered the losses were most likely d/t a broken hydrometer… our Salinity was sky high after a water change! My deepest apologies. Might give it another go soon, will update my findings.I have used this product for the past 2 weeks in my 125 gallon reef tank. I dosed 12 ml every three days. This is a review for the marine version used in a saltwater tank.This tank has been established for over 1.5 yrs and got my first outbreak of GHA that came in on a coral we recently bought. My ammonia is zero, nitrite is zero and nitrate under 20. My phosphates read zero in both the RO/DI water and in tank. Not only is the GHA growing and spreading like a weed still, we now have a massive cyano outbreak to boot since we started using it! We have also lost all of our turbo snails (more than 10), all 4 emerald crabs, peppermint shrimp, and horseshoe crab. All of the mushrooms, hammer coral and open brain are as shriveled as can be 🙁 All the fish seem to be ok, a skunk cleaner is still ok and hermits are ok. The rest of the LPS coral is ok but not happy. We do not have any SPS. Kicking this product to the curb and today after 20% water change we added chemi-pure elite and purigen in hopes that will absorb the rest of the algaefix marine and any phosphates/nitrates that may be reading false d/t algae consuming it.PS: I ran the skimmer throughout the entire treatment and ran carbon the first week. I feed once daily alternating Brine Shrimp with PE Mysis. One cube shared between 1 Large Engineer Goby, 2 Banggai Cardinals, 1 Black Phantom Clown, 1 Yellow Headed Jawfish, 1 Yellow Tang, and 2 Squarespot Anthias.
Dave –
Great for bubble algae
Good value for what it does. Took care of my bubble algae problem quickly.
Maureen Dean –
After 1use I can notice the algae dying in the fish pond. We had a big problem with algae but this product seems to be fixing the problem.
Subhajit Ghosh –
Fine
Vimarshan akula –
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Margaret skitt –
This product Algae Fix Marine has the same ingredients as the one for Fresh Water fish tanks. I have used both. They work very well. Corals, fish etc are not affected by it. I believe Vibrant is the same, but much more expensive. I donât know why I bought such a big bottle as I only need 10 ml for 100 gallon marine tank.
sisodiya siddarth –
Good