Pond string algae types cause different problems
String algae are present in ponds and the worst of these is blanketweed ... because these algae do not circulate through the UV tube they are not effected at all by UV light. Pond algae sticking to pond walls and other surfaces are natural ... don't try to remove it
Non-Circulating Surface Algae ...Algae that grow to about 1 cm in length and are seen on pump surfaces, rocks, pump filter sponges and the sides of ponds are normal. Do not try to remove them by sweeping the pond walls for example because they will keep coming back and if left alone reach an equilibrium point. The fish love them and the balance of the small pond is improved.
They can be a bit unsightly sometimes but this is natural. They will not damage your pond environment. An UV light will not affect these algae in any way because they stay in one position and are NOT exposed to the UV light.
Dreaded Blanketweed ... The enigma of blanketweed.
Blanket weed is that long slimy algae that seems to grow and grow and can never be eradicated.
Heres a picture of what it looks like in close up it consists of long thin strands which as you can see are made up of single cells in a straight line. These strings grow like crazy.
When it is fished out of the water it looks like this; yes a wet blanket and hence the name blanketweed:
Often even when there is lots of blanketweed the water is crystal clear. This is because the blanketweed is starving other algae out of existence, helped by reducing light penetration through the floating blanket
By improving the balance between plants in the pond and reducing fish density and therefore reduced feeding the tendency to get blanketweed will be reduced but not necessarily eradicated. Plants in ponds compete with the algae for the "fertilisers" produced by the fish as explained earlier.
Water quality certainly plays a role in blanketweed development but this is not the whole story since even the best pond keepers can get this problem. I do have a good solution so long as you follow the instructions below. It involves barley straw and while many people have heard of this treatment not many understand the circumstances under which it works. Failure to understand may well result not only in failure to control blanketweed but also in fact to create other pond problems.
Be careful when buying chemicals to kill blanketweed - make sure they do not kill anything else including plants, fish, filter bacteria, birds that drink the water etc. Buy the low cost combo pond filter and UV containing Alfagrog or Supra as it's called in USA
"The Complete Pond Solver" by Tony Roocroft
2005 Edition. Essential reading for anybody who wants or has a garden pond. Get 12 Excel pond calculators free as well as "Water Lilies and Pond Aquatics" ebook also free
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