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API Pond Algaefix Algae Control Solution, 1-gal bottle

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About This Item

Details

  • Effectively controls green water algae, string or hair algae and blanketweed in ornamental ponds.
  • Helps keep ponds, water gardens and ponds clean and clear.
  • Algaecide controls existing algae and helps resolve additional algae blooms.
  • This algae solution is safe for live plants and pond fish.
  • Do not use with freshwater crustaceans, including shrimp, crabs and lobsters.

Instructions

FAQ

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Special Note
  • 8-oz bottle treats up to 2400 gallons.
  • 16-oz bottle treats up to 4800 gallons.
  • 32-oz bottle treats up to 9600 gallons.
  • 64-oz bottle treats up to 19,200 gallons.
  • 1-gallon bottle treats up to 38,400 gallons.
  • 2.5-gallon bottle treats up to 96000 gallons.

About API Pond Algaefix

Why Use API POND ALGAEFIX Algae Control?

Algae growth can appear as “green water” blooms, “pea-green soup”, filamentous algae on plants, or as floating mats known as blanket weed. Algae grows when there are excess nutrients in the water—usually in spring prior to plant growth or during summer in direct sun. API POND ALGAEFIX Algae Control works quickly to control algae growth and keep ponds, water gardens and fountains clean and clear.

Controls Most Types of Algae

Before Using

Make sure your pond has vigorous aeration to avoid fish loss due to low oxygen levels. When algae is controlled and removed by the filter or settles to the bottom of the pond, oxygen may drop to harmful levels without adequate aeration. Pond water also carries much less oxygen in warm weather.

Algae Types

API POND ALGAEFIX helps control three main types of algae:

1.    Green Water Algae (Chlorella)

2.    String or Hair Algae (Cladophora)

3.    Blanket Weed (Oedogonium)

How to Use API POND ALGAEFIX Algae Control

Treating your pond to control algae is simple. For best results, be sure to read and follow all label directions.

Step 1

Vigorous 24-hour aeration is required during treatment. Do not shut off pond pumps or aeration devices at night.

Step 2

Remove as much algae as you can by hand before treating your pond.

Step 3

Disperse API POND ALGAEFIX evenly around the pond and thoroughly mix it into the water. DO NOT OVERDOSE.

Step 4

As algae dies off, remove as much of the dying algae as possible.

Calculate Pond Volume Before Use

To ensure accurate dosing, determine your pond’s volume and then use the dosing chart to figure out how much API POND ALGAEFIX to use. For square and rectangular ponds: avg. length (feet) x avg. width (feet) x avg. depth (feet) = cubic feet of water. Cubic feet of water x 7.5 = volume in U.S. gallons. For round ponds: top diameter (feet) x bottom diameter (feet) x height (feet) x 0.785 x 7.5 = volume in gallons.

About API

The team at API has a passion for fish and understands the rewards and relaxation fishkeeping can bring. For almost 60 years, they have developed premium products with a focus on proven and effective results. API offers a range of testing kits, water conditioners and nutritionally superior fish foods. They are dedicated to making a better underwater world for the benefit of fish and those who keep them.

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Questions & Answers

14 Customer Questions

My pond is fully covered with algae. It also has some weed. Will this product solve both problems? How often do I use if my after 1st treatment?

Does this product kill Duck Weed?

Hello! Should AlgaeFix and the sludge remover (EcoFix, I believe) be used at the same time, or should the sludge remover be added after all the Algaefix treatments are completed? Thank you!

Answer by Chewy • Apr 20, 2018
It is best to use this supplement on it's own until the algae is controlled.

CAN I USE THIS ON MY INDOOR KOI TANK, 120 GALLON?

Answer by Chewy • May 01, 2021
This solution is designed to be used on ponds, water gardens and fountains.
Reviews
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4.5
Rated 4.5 out of 5 stars
471 Ratings
Terms & Conditions

207 Customer Reviews

Rated 5 out of 5 stars
Verified Purchase
By Tubwater on Jul 30, 2021

Very Effective

I bought a house with a 3000 gal koi pond/fountain not long ago. The pond is equipped with 2 stages of filtration. The previous owner fought murky green water

I bought a house with a 3000 gal koi pond/fountain not long ago. The pond is equipped with 2 stages of filtration. The previous owner fought murky green water for years with limited success. The very large, brightly colored Koi were barely visible. I started looking for an algaecide and settled on API Algae Fix. Within a few weeks the pond was crystal clear and remains so with regular treatments. I read several comments about the danger to fish. I have several large, valuable Koi so I was very careful to follow instruction about dosing. I measured the pond carefully to get an accurate water volume including the volume in the filtration and circulating system to determine the proper dosing. My pond is also equipped with a secondary aeration system which ensures adequate O2 saturation. This product is very effective and safe for fish but the buyer should follow the directions and warnings carefully. I am very satisfied with the product.

Rated 5 out of 5 stars
Verified Purchase
By Debbie on May 12, 2025

Destroyed Algae in less than 24 hours

Wow. I was having a real problem in my pond for almost a week until I read the side of my API Pond Ecofix Sludge Destroyer and it said if the problem is bad, first

Wow. I was having a real problem in my pond for almost a week until I read the side of my API Pond Ecofix Sludge Destroyer and it said if the problem is bad, first use API Pond Algaefix Algae Control Solution. I ordered it and it doesn't take much for the size pond I have. I added it and the next day my pond was clear. The second day, I could see every acorn and leaf on the pond bottom. A few days later, there was a small amount of green floating on top, so I treated it again and now, the water is clear as a bell. This works wonderfully.

Rated 5 out of 5 stars
Verified Purchase
By Michael on Jun 23, 2025

It works!

Algae started to die off, losing its color gradually fading to a very light tan almost white, during which time I had to remove the dead algae from the pond and

Algae started to die off, losing its color gradually fading to a very light tan almost white, during which time I had to remove the dead algae from the pond and filter almost daily. Just mind the dosage.

Rated 5 out of 5 stars
Verified Purchase
By sancalva on Mar 23, 2023

clears water

this is hands down the best way to clear up algae. follow the directions! dont add more thinking it will work faster. it will, and it will kill your fish and plants

this is hands down the best way to clear up algae. follow the directions! dont add more thinking it will work faster. it will, and it will kill your fish and plants you want. take the time to do it right, it clears up water and fish and plants you love thrive. but read the label, know your pond water volume and measure. i have been using this for 10 yrs or more now. start in spring, get on top of it, then occasionally add as needed , if needed in summer to fall.

Rated 2 out of 5 stars
Verified Purchase
By robyn on Jul 3, 2022
Top 1000 Contributor

Don't use of animals drink

It helped clear algae from my pond,but at the cost of all the animals I take care of suddenly no longer using it. They refuse to drink (or swim) and have gotten

It helped clear algae from my pond,but at the cost of all the animals I take care of suddenly no longer using it. They refuse to drink (or swim) and have gotten to climbing the bird bath instead of my 15x22' pond.:/ Built just for them. Used this with another of the company's algae product. Stated safe for animals. They're telling me different. Attaching a pic from before I used product. They used to love the pond before the second dose of this stuff. And a night vision shot of how desperate the raccoons are after I put in this stuff. Sucks

Rated 5 out of 5 stars
Verified Purchase
By MamaHawk on Jun 15, 2020

Best Stuff Ever

There are innumerable products on the market that claim to rid a garden pond of algae. This is the only product with which we have had success . . . complete success!

There are innumerable products on the market that claim to rid a garden pond of algae. This is the only product with which we have had success . . . complete success! I dose the pond once a week according to the directions, and that's it. No other work to do. I LOVE this stuff.

Rated 5 out of 5 stars
Verified Purchase
By Heinrich on Mar 22, 2017

Works as advertised

This product got rid of my string algae as well as the unicellular, blue-green kind that forms a yellow-green scum on the pond surface, with just 4 applications

This product got rid of my string algae as well as the unicellular, blue-green kind that forms a yellow-green scum on the pond surface, with just 4 applications spaced 3 days apart. I had tried in vain to control the latter kind with barley straw, and spent more money fighting the former with hydrogen peroxide than I do now by eliminating both with Algaefix. This is better than I had expected.

Rated 5 out of 5 stars
Verified Purchase
By CHRISTINE on Jul 11, 2021

Outstanding purchase

I was amazed at the purchase I made for some very expensive pond algae preventer. Algaefix is the best product I have found to prevent algae growth in our pond

I was amazed at the purchase I made for some very expensive pond algae preventer. Algaefix is the best product I have found to prevent algae growth in our pond. We have a 10,000 gallon pond so we go thru a lot of this stuff. When I found it online at Chewy the price was not to be believed! I saved a bundle and they shipped it in a day! I will always check Chewy's prices now before I purchase anything for my pond!!!

Rated 5 out of 5 stars
Verified Purchase
By Carol on Jul 27, 2025

GREAT PRODUCT

Works great at controlling algae. Price was good. Shipped in a plastic zip lock bag in case there was a leak.

Works great at controlling algae. Price was good. Shipped in a plastic zip lock bag in case there was a leak.

Rated 2 out of 5 stars
Verified Purchase
By Unhappy on Sep 25, 2020

No death and destruction

Pond still full algea. Received it on 9/10 and put the first treatment in on that date. I have a 1200 gallon pond and so 4oz per treatment. I have been doing this

Pond still full algea. Received it on 9/10 and put the first treatment in on that date. I have a 1200 gallon pond and so 4oz per treatment. I have been doing this every 3 days per the instructions and have vacuum the pond 2x already to make sure there is no dead stuff or waste feeding the algae. Am getting ready to put another treatment today and vacuum, but now I don't think there is a point as I see little that needs vacuuming. I have Koi in the pond and at least they have had no issues or death. Only reason I did not give it 1 star is because the algae has not gotten worse and am trying to stay optimistic after spending $107 that at least it's helping out a bit.