ALGAE BUILDUP IN HORSE WATER SOURCES
QUESTION: My horses automatic waterer gets a horrible buildup of green slime. What can I do about it?
ANSWER: Algae is created partially by Sunlight (thus often worse in the summer). And the nutrients entering the water from the livestock's mouths when they drink. Also from bugs, leaves, grass and other things that end up in the water source. It is a year round problem because of Nitrites being converted to Nitrates, which along with the sunlight creates Algae.
Just flush when ever you have a chance and scrub with a stiff, bristle brush. Then flush again through the bottom drain on the waterer.
Nothing you can do about it without adding chemicals (which may not be 100% tested for 100% safety for livestock)! I have success by switching my large water tanks quite often. Emptying the one with the Algae growing on the bottom and sides and leaving it to dry completely and thoroughly in the sun. Direct sunlight without the necessary water dries and kills the existing green slime.
You will get this ALGAE build up in the winter too with any heated tank, perhaps not as bad because less hours of sunlight, no bugs landing in it, tree leaves, etc. blowing into it.