CrystalClear® AlgaeOff® String Algae Remover
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California Residents, please click here for AlgaeOff® California.
$11.99 - $119.99


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  • Details
  • Usage
  • Videos
  • Reviews
  • Immediately Removes String Algae
  • Reduce Timely Maintenance
  • EPA Registered Algaecide

CrystalClear® AlgaeOff® utilizes the latest in oxygen technology to remove and kill string algae on rocks, streams and waterfalls. CrystalClear® AlgaeOff® is an EPA registered granular algaecide that works in seconds at any water temperature! In addition to removing algae, AlgaeOff® adds oxygen to your pond and removes odors.

Live in California? Check out AlgaeOff® California

Usage Information

From dosage rates to product labels, the USAGE tab contains all of the information you need to properly apply your pond care products.

CrystalClear® AlgaeOff® 8 Ounce
8 Ounces
CrystalClear® AlgaeOff®1 Pound
1 Pound
CrystalClear® AlgaeOff® 2.5 Pounds
2.5 Pounds
CrystalClear® AlgaeOff® 10 Pounds
10 Pounds
CrystalClear® AlgaeOff® 25 Pounds
25 Pounds
Application Powder Powder Powder Powder Powder
Active Temp None None None None None
Square Feet Treated Up To 200 Up To 400 Up To 1,000 Up To 4,000 Up To 10,000
Shelf Life 5 Years 5 Years 5 Years 5 Years 5 Years

Dosage Rates

Surface Area (Square Feet)
AlgaeOff® - Light Growth
AlgaeOff® - Heavy Growth
25 - 50 1/4 cup (2 oz) 1/2 cup (4 oz)
51 - 100 1/2 cup (4 oz) 1 cup (8 oz)
101 - 150 3/4 cup (6 oz) 1-1/2 cups (12 oz)
151 - 200 1 cup (8 oz) 2 cups (16 oz)
200 - 250 1-1/2 cups (12 oz) 2-1/2 cups (20 oz)
Up To 500 1-1/2 lbs (2-3/4 cups) 2-1/2 lbs (4-3/4 cups)

The included scoop is 1 ounce.

How To Apply

Water Gardens: Apply AlgaeOff® directly over the infested area in granular form. Surface should be wet or water should be applied immediately following application. For waterfall applications, turn off waterfall pumps and allow AlgaeOff® to sit on the waterfall for a period of 20 minutes and then turn pumps back on.

Skim the dead algae or organic material that rises to the water's surface after treatment. Allowing dead organics to sink and decay will provide a food source and additional nutrients for future algae blooms. Allow 48 hours between consecutive treatments.

For liquid applications, please follow all label instructions. Due to solubility, AlgaeOff® is not as effective with this application method.

Ponds & Lakes: Treat floating or submerged algae mats evenly from shoreline out. If the majority of your pond is covered, treat half of the algae infestation; wait 10-14 days before treating the second half. Heavy growth may require retreatment. *NOT recommended for Chara treatments.

When To Apply

AlgaeOff® California should be used any time string algae has accumulated on rocks, streams and waterfalls. Water temperature has no effect on AlgaeOff® California, but higher temperatures enhance effectiveness.

When To Apply

AlgaeOff® should be used any time string algae has accumulated on rocks, streams and waterfalls. Water temperature has no effect on AlgaeOff® but higher temperatures enhance effectiveness.


After application, do not allow undiluted AlgaeOff® granules to remain in an area where humans or animals are exposed. Make sure all granules have been sprayed with water to fully dissolve.


What others are saying

5 out of 5

Customer Rating

"Waterfall Looks Great!"Shane of Girard, KS

After using a couple products to remove the string algae from my waterfall & stream rocks, I tried Algae-Off. IT WORKS! It is easy to use, works great and now is a regular part of my pond routine.

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5 out of 5

Customer Rating

"Algae Gone"Sandy Anderson of Jericho, VT

After a long hard winter in northern Vermont, iceout resulted in a goodly growth of string algae along with slightly off colored water. I was amazed at the effectiveness of Algaeoff as the algae and other muck floated up for easy removal. Alternate treatment with seasonal defense has cleared the water and now that I have treated with both of these products twice, life in the pond is pretty much perfect. Excellent results.

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1 out of 5

Customer Rating

"AlgaeOff String Algae Remover"Mack Barnhardt of Las Vegas, NV

Was not impressed, tried it in a small area and had no real good results. After reading about health issues with animals it just doesn't seem right to put in with fish or expose my wildlife or dogs to it. ***Comment from The Pond Guy - AlgaeOff must be applied directly over string algae on a damp or wet area with the waterfall pumps turned off for 20 minutes to activate the product. We offer 100% satisfaction guarantee, contact our customer service for details.***

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