Hair Algae is an unwelcome site in most ponds.
Its thick mats and wavy green strands can be unsightly, but most importantly are usually an indication that the pond is out of balance meaning there is too many nutrients for the pond to adequately dispose of before the algae can feed on them.
Hair algae will coat most anything, from the rockwork and substrate at the bottom of the pond, to the ornamental plants you are trying to grow and only grows in shallow water where sunlight can penetrate to the bottom.
The biggest mistake people make when dealing with hair algae is thinking they can fix it with chemicals.
Algaecides can be an effective short term treatment, but you have to be cautious that you do not use chemicals that can harm any animal or plant life and the resulting dead algae must be removed before it can fuel more algae growth.
The primary culprit behind hair algae growth is nutrient rich water.
Often this is caused by overstocking and/or overfeeding fish in the ponds.
For this reason it is important to have proper filtration and abundant plant life (not algae) in the pond to help filter out and remove excess nutrients before the algae can utilize them.
Biological filters are very effective as they create a suitable breeding ground for beneficial bacteria to break down and degrade waste, while plants will make use of available nitrates and phosphorus before algae can use them.
Another means of dealing with hair algae is through proper aeration...
Algae thrive in oxygen depleted, stagnant water, which can also lead to poor water quality, and soon stressful, disease-inducing conditions for your pond-fish.
Proper aeration will both add essential oxygen into the pond, but will also help to circulate the water reducing stagnant areas.
There are different ways to add aerate your pond depending on its size such as waterfalls, fountains or true aerations systems.
A final consideration should be given to the amount of sunlight your pond receives.
Ponds that receive a great deal of sunlight often encounter more problems with algae.
Since algae is a plant, it requires sunlight for photosynthesis and growth.
The addition of floating pond plants or pond dyes can greatly reduce the amount of sunlight penetration into the pond water and can reduce the growth of the algae.
Pond dye is most commonly blue in color, but black is growing in popularity, and is safe for plants, and fish and are non-staining once mixed with water.
Hair algae can be a nuisance, but if encountered, it can be a blessing in disguise.
The best method of controlling it is prevention.
Use this opportunity to fix a possible life threatening condition before it progresses and you should experiences years of successful ponding.