(818) 541-9944

5 May 2016


So Cal Ponds, Inc. logo on a white background
So Cal Ponds Inc.
5 May 2016 

So you have string algae in your pond? You may be concerned because the pond might not look as nice as it had in winter. That is not necessarily a bad thing. Ponds are a delicate ecosystem which rely on a number of factors to remain balanced. If any one of these factors tips too much to one side the entire ecosystem will become unstable and many symptoms will become obvious.

Here in So-Cal we get plenty of sunshine and warm weather. These are perfect growing conditions for both “string algae” and “pea soup” algae. Both types of algae can be an indication that there is an imbalance in the pond.  Let’s focus on string algae since it is the most common type of algae we experience and the number one reason we receive a phone call from a concerned client.

There are two common types of algae in your pond

  1. Phytoplanktonic (free-floating) algae is known as “pea soup” or more visually when the pond water is completely green. This type of algae is not the most common in So-Cal but we do see it often enough.  This type of algae is common in new ponds when the nitrogen cycle is unstable or during the sunny days of summer.  This is due to the filter being unable to process the ammonia in the pond due to a lack of a healthy colony of beneficial bacteria.
  2. Benthic (attached) which includes “string algae” or “horsehair algae”, “water net” and “blanket weed”. Here in So-Cal this is what we see the most.  Physically removing string algae is the best way to keep this algae under control, however, the action of removing the algae causes reproductive spores to be released into the pond causing the cycle to continue.

This could mean the pond is overpopulated with aquatic life, is under-filtered or the filtration system is not properly being maintained, has a lack of aeration or just has an abundance of organic matter such as leaves and debris leftover from fall and winter.

Algae typically grows when there in an abundance of nutrients in the water, there is a lack of oxygen or an imbalance in the ecosystem. Excessive nutrients could be caused  by many things such as leaf matter, an over population of fish and other aquatic inhabitants, low oxygen levels, poor circulation and/or filtration or lack of regular maintenance . If any one of these is left unchecked the pond may start to grow algae to consume the nutrients and try to balance the ecosystem… think of it as Mother Nature’s filtration system.


So how do we prevent algae from taking over the pond? Good question. There are many different products that will slow or reduce algae growth but nothing is better than keeping the pond clean. We, at So-Cal Ponds Inc., prefer to maintain a natural healthy system without the need for harsh chemicals or additives.  Removing organic matter such as leaves, fish waste, uneaten food, dead aquatic life (such as fish and plants) will help limit the amount of “food” or nutrients the algae will have to grow.  If your pond is equipped with a skimmer it should be checked and emptied, removing the leaves as soon as possible. Your ponds pump/s should be checked and regularly maintained to ensure they are maintaining their optimum flow rate. The pond’s filtration system should be cleaned and serviced on a regular basis to remove accumulated waste and maintain proper water flow.

There are additives that can be added to the pond such as Algae Fix,  Algae Off, Barely Straw and salt which will help kill or reduce algae growth. These additives are a quick and effective way of preventing the algae from taking over your pond, however once the algae is killed off it should be removed from the water to prevent it from becoming part of “the circle of life” and aiding in the growth of new algae blooms.  Any product designed to kill algae will also harm most aquatic plants that are in the pond and should be used with caution.


  1. Algae in your pond is caused by excessive nutrients in the pond such as leaf matter, fish waste, uneaten food, or fertilizer run-off.
  2. Algae in your pond is not a bad thing. Think of it as Mother Nature’s filter.
  3. Algae should be encouraged, just maintained.

If  you still have a question about algae, your pond or the causes of algae, leave a comment or give us a call.


So-Cal Ponds is here to help.


10164 Tujunga Canyon Blvd. Tujunga, CA 91042

(818) 541-9944

Mon-Fri: 8:00 AM - 5:00 PM

CA C27# 991368

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