Green Pond Water, String Algae, Hair algae, etc.

Pond Algae comes in many different forms, even different colors (Green Algae, Red Algae,Brown Algae). The two kinds of Pond Algae frustrating backyard Pond owners most often, though, are “Green Water Algae”(also called Pea Soup Algae) and “String Algae” (also called “Blanket Weed” or “Hair Algae”).

Controlling and getting rid of String Algae and Green Water Algae in ponds used to be difficult, but in the last few years many effective and environmentally safe products have been developed to eliminate String Algae and Green Water Algae. This makes it much easier to control and eliminate the String Algae and Green Water Algae nuisances.

Green pond water Algae are single cell plants that can make the Pond look like “pea soup”. These plants are so tiny that they can pass right through a Pond Filter. Consequently additional forms of Algae Control have to be used. Algaecides are not a good choice in the Garden Pond or Water Garden, because they will also harm Pond and Aquatic Plants. Algaecides in Fish Ponds and Koi Ponds can be harmful to the Pond Fish.

It is very important to balance the pH in the Garden Pond (it should be between 7.0 and 8.0). Nothing in the Pond will be very successful until this first step is taken. Easy to use Pond Test Kits are available to measure the pH.Pond Algae in its many forms (green “pea soup” pond water, string algae on waterfalls, pond plants, liner and other pond surfaces) and pH are inter-related. The higher the pH, the more algae of some sort or another the Water Garden, Fish Pond or Koi Pond is likely to experience.Here are the steps to take to help eliminate the various kinds of Pond Algae:

  • Balance the pH to between 7.0 and 8.0 (always measure pH in the morning, it goes up during the day).

  • Eliminate nutrient sources by using a good Beneficial Bacteria product and skimming out organic debris.

  • Use a “Flocculant” to clump single cell green water algae so it gets heavier and falls to the pond bottom to be picked up by the filter.

  • Use a fish safe Oxygen Cleaner to clean your waterfall, pond liner and other surfaces without scrubbing

  • Add lots of Pond Plants to shade the pond water.

  • ***The only sure way to eliminate green water in a Garden Pond, Fish Pond or Koi Pond is with an Ultra Violet (UV) Clarifier

Once the pH is balanced you can introduce Beneficial Pond Bacteria (read about Beneficial Pond Bacteria in the Pond by clicking here) and lots of aquatic plants to compete with the Algae for nutrients and hopefully starve the green water Algae. (It is important not to clean the Pond filter with chlorinated tap water – this will kill the beneficial bacteria. Use a bucket of Pond Water instead).

Flocculants are available that are harmless to Pond Fish and Pond Plants, but make the Algae clump together so it can be picked up by the Pond filter. It is advisable to clean the Pond filter more regularly for few days after using the product, so the green water Algae can be efficiently eliminated.

Ultra-Violet-Clarifiers are modern mechanical devices that eliminate green water Algae for good. These UV lights are used in conjunction with a good Pond Filter to kill and then remove the algae from the water.

String Algae (or Blanket Weed or Hair Algae) often grows in water with high pH values. The pH must be lowered to 7.0 – 8.0 to slow the growth of this type of Algae. There are many products available to eliminate existing string Algae safely without harming the Aquatic Plants in the pond. Oxygen Cleaners are best to clean existing stringy growth on Waterfalls, pond liners and other Pond surfaces without scrubbing, Barley products will help prevent future string algae growth.


Click on Images to Shop for Algae Control items now.