Algae Defense - 1 gal by Pond Logic

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*Cannot ship to AK, CA, CT, DC, HI, ME, NJ, NY, PR, RI, WA. Usually Ships within 24 hours.
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  • Algae Defense Aquatic Algaecide for control of filamentous "string" algae, chara, and planktonic "pea soup green water" algae
  • Algae Control with Algae Defense
  • Algae defense instructions
$49.99 - $62.99


Algae Defense by Pond Logic 1 gallon

Algae Defense algaecide eliminates algae blooms and green water from your pond.  This fast acting Algaecide can be applied directly using a tank sprayer for filamentous algae (string algae) , chara, and planktonic algae (green water algae). Should be used when water temperatures are at or above 60 degrees for best results. 

Unless steps are taken to reduce the overall nutrients in the pond, multiple applications may be needed for a full season of control.


**For best results, use with Treatment Booster™ PLUS.**

Expect to see results within 7-10 days. As string algae dies, it releases from the bottom of the pond. You will see floating mats of brown algae appear in the pond. This can be removed with a pond rake or can be digested naturally with MuckAway beneficial bacteria.

Algae Defense Usage:

Mix with Water & Treatment Booster in a tank sprayer. Spray algae directly. For deeper water, place sprayer's tip beneath the water's surface.

Only treat up to half of the pond surface, waiting 10 to 14 days before treating the second half. In hot weather, or when fish are stressed, treat 1/4 to 1/3 of pond at a time. 

When is the best time for treatment?

Algae Defense works best when applied to water that is above 60 degrees. Treat early on a clear sunny day for best results.


Algae Defense® Dosage Rates
Treatment Area     
(In Square Feet)
Algae Defense   
(In Gallons)
(In Gallons)
2,000 Sq. Feet ¼ Gallon 2½ Gallons
4,000 Sq. Feet ½ Gallon 5 Gallons
8,000 Sq. Feet 1 Gallon 10 Gallons 

For best results, use with Treatment Booster. Mix 2oz of Treatment Booster per gallon of treatment mixure(treatment and water).

Use Pond Dye after Algae Defense Treatment to limit new algae from returning to your pond.

Water Use Restrictions: None

Other Restrictions: Do NOT use in ponds with koi, goldfish or trout unless carbonate hardness(KH) is above 50 ppm.

Shipping Restrictions: Algae Defense® cannot be shipped to AK, CA, CT, DC, HI, ME, NJ, NY, PR, RI, and WA.


Algae Defense Product Label and Detailed Application Instructions


As with all of our products, we offer free technical support.

If you have questions about this product, e-mail us at and we will get right back to you.

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Additional Information

Pond Size:
up to 1/5 acre
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3 Reviews

  • 5
    Very pleased couldn't imagine how well it worked

    Posted by John Snell on Jun 22nd 2018

    Very satisfied

  • 5

    Posted by William Beinhower on Jun 29th 2016

    This spray is amazing. I used it twice this. It cleared everythin up.

  • 5

    Posted by Unknown on Mar 22nd 2016

    We spent countless hours each week trying to clear the scum and debris from our algae infested pond. It looked terrible and it smelled awful. Now our pond is clear and beautiful thanks to Algae Defense. The fish aren't harmed by the chemicals either. It's a win-win!

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