What’s So Special About String Algae

Of the myths that often get bounced around regarding pond care and management, there seems to be one that the issue of string algae is more difficult to treat or control that other types of algae.

To be sure, Filamentous algae, Spirogyra, Anabaena, Oscillatoria, Lyngbya, Pithophora or string algae as most pond owners call it, can look terrible in a pond.  With it’s long strands spreading up from the bottom or swirling around the top of the pond, it can make the best of ponds look like an infested bog.

On top of this many folks seem to think that this particular type of algae is more difficult to treat than the other common issues like green water. 

Truth be told though, it’s not really anything special.  In fact we often take the approach that since all algae is generally supported and maintained by abundant nutrients in the water, then at least in terms of natural solutions to algae control, we view all algae pretty much the same.

In other words, when you cut off it’s food supply, you reduce or eliminate the algae growth.  This can work equally well in various types of algae that have no roots.  This means they derive their support directly from the water itself, and this makes them vulnerable to natural solutions that lower nutrient loads in the pond.

So the real secret and the real variable, isn’t the algae itself but the reasons or causes of why the nutrient load in the pond might be high. 

Is it too many fish in the pond for it’s size?  In that case, you might want to reduce the fish stock and see if that helps.  We recommend no more than 1 inch of fish per 10 gallons of water in a pond or no more than one inch of Koi in 25 gallons of water.  Any more than this and you may be overstocked.

Then too, you might find that the pond is getting a lot of sun exposure during the day.  This too can stimulate algae growth and help it along if nutrients are present to support it.  An aquatic dye may help reduce this photosynthesis activity caused by the sunlight.

And what about leaf or grass debris?  This type of organic “garbage” can really help algae take off since during it’s breakdown in the pond it is sure to raise nutrient loads quickly.

These are just a few of the areas to consider but by doing this, you really are targeting the root of the problem and not just the symptom of whatever algae you’re looking at.

Here’s one final comment about string algae and filtration.  Many people buy UV or Ultraviolet filtration under the assumption that it helps control all types of algae.  This isn’t quite true.  UV will not help with string algae since the algae mass can’t pass through the filter itself.  UV will work on green water quite often however.

Also, of the newer technologies, Ultrasonic algae control is gaining acceptance and accolades.  It will work on string algae, but it can take some time to do so.  Simply put, since it must work it’s way through the algae mass, bit by bit, it’s sometimes better to remove or kill algae directly, then apply the ultrasound to keep the algae from forming again.  In terms of green water, ultrasound can work quickly and effectively.

Taking a simple approach to algae control is often better than a more complicated one.  So in simple terms, think of algae as well, just algae…nothing special, no matter what it may look like.  If you target the root of the problem, so to speak, you can rest assured that most algae will be kept under control without using harsh chemicals or algaecides.