From fhotd member cowgirl4him
http://fhotd64476.yuku.com/topic/4028
For cleaning water troughs use a 4" paint scraper to get the crud off the sides and bottom of the tank, this works better than a brush or sponge.
To keep algae from growing put your tank where it gets full shade, like in your run-in shed. If you have to put it in the sun, try to float a piece of foam rubber on the top to shade the water. I use cheap 3'x3' jigsaw pieces we had for a childs play area.