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Monday, September 20, 2010

String Algae Problems?

If you are having a trouble with string algae taking over your pond, chances are that you have a layer of gravel covering the bottom.

Why ponds with rock at the bottom don't work

Imagine you take a dog and place it in a room with six inches of gravel for a floor.  Now you keep feeding the dog while letting its waste settle in the rock.  You keep feeding it and feeding it, and eventually, it's going the waste is going build up and turn the room toxic.

A pond with rock at the bottom is very similar to that situation.

Waste gets trapped between the small spaces between the rock.  Anaerobic bacteria break the waste down  and turn it into Nitrate (plant fertilizer.)  The string algae uses the Nitrate in the water as a catalyst to spur its growth.  A by product of the anaerobic bacteria breaking down the waste is Hydrogen Sulfide.  Pockets of Hydrogen Sulfide will build up in the mulm at the bottom of the pond.  When the pond is cleaned out, the pockets for gas escape and poison the fish (it's the rotten egg smell.)

In a natural aquatic setting, for example: a river, a stream or a lake, thousands to millions of gallons of water are replaced each day.  There is enough water flowing through a a natural ecosystem to keep the level of waste at an absolute minimum while supporting aquatics life.  A small pond in a backyard with a rubber liner and rock covering the bottom is not a natural aquatic setting.  In a lake, there is tens of thousands of gallons of water per fish.  In a backyard pond, there usually only a hundred gallons of water per fish.

How to get rid of string algae

Remove the rock at the bottom of the pond and install a bottom drain along with a filter system.  Waste will get sucked into the bottom drain and captured by the filter.  If fish waste and other organic debris is removed from the pond, the string algae will have nothing to fertilize its growth.

Filter System Components

A complete filter system will include mechanical, biological and UV components.  Mechanical filters will remove the solid waste from the water, biological filters will handle the Ammonia that fish produce and UV sterilizers will eliminate the free floating algae that cause green water.  They work together to keep pond maintenance at an absolute minimum.

A poorly designed pond will require you to muck it out on a regular basis.  This is not water gardening, it is pond garbage removal.

1 comment:

honeal81 said...

As a koi fish grower enthusiast, I'd like to add something based on my personal experience...In small doses, algae can help add oxygen into your pond water. During the day, in the photosynthesis process, it allows these green plants to produce oxygen. Algae also feed on the nutrients of the water which, in turn, some of the fish often nibble on. Another good thing about having these in your pond is that it can give a more natural look to the setting. However since they feed on the nutrients of the water, when the nutrient level becomes high, an algae bloom (an excessive occurrence of algae) may arise along with the oxygen content in your pond. When an algae bloom suddenly occurs, never clean or use tap water for a partial water change because this will kill the beneficial bacteria that are already present in your water. Changing all the water at once can only aggravate the situation so make sure you only do partial changing using well water. Works for me!