CrystalClear<sup>®</sup> AlgaeOff<sup>®</sup> String Algae Remover

CrystalClear® AlgaeOff® String Algae Remover

Kill String Algae

  • Immediately Removes String Algae
  • This Pond Algae Killer will 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 algae remover that works in seconds at any water temperature! In addition to string algae control and removal, AlgaeOff® adds oxygen to your pond and removes odors.

Tech Specs

Usage Information

CrystalClear® AlgaeOff® 2.5 Pounds
2.5 Pounds
CrystalClear® AlgaeOff® 10 Pounds
10 Pounds
CrystalClear® AlgaeOff® 25 Pounds
25 Pounds
Application Powder Powder Powder
Active Temp None None None
Square Feet Treated Up To 1,000 Up To 4,000 Up To 10,000
Shelf Life 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 during hot weather or when treating heavy growth, it is important to treat no more than ¼ of your pond at a time and wait the full 14 days before re-applying. This helps lower the risk of fish loss during hot weather or when treating heavy growth. Heavy growth may require re-treatment. *NOT recommended for Chara treatments.

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.


Replacement Parts

Here are the replacement parts for CrystalClear ® AlgaeOff ® String Algae Remover.

Weeds Treated

The first step towards effectively treating any pond weed is proper identification. CrystalClear® AlgaeOff® String Algae Remover is recommended for use against each of the weeds listed below. Click on your desired weed for more information and alternate control options.