A very small amount of non scented bleach or hydrogen peroxcide can safely be used for cattle. not sure about goats. I also know farmers that will put a trout or perch in there for the summer to est anything in there
Is there any place you can put the bucket in shade? Without enough sunlight the algea cannot live. Also a small fish (goldfish or guppies) in the bucket will eat any larvae. And the mosquito larva can take up to 7 - 10 days to mature into a full grown mosquito.
Put some bleach in them. The bleach should keep the algae from growing. If you get a 55g. barrel and attach a little automatic waterer into it so it's like a trough that the can drink out of but fills itself when it gets down to a certain point, then you could put some fish into it. That way you clean it less and because it's 55g. then you don't need to change it all the time, and the fish will eat the algae as it grows.
Elevan, is this the barley straw treatment you use??
They sell this at the feed stores.
I was thinking of getting some of this today since we have a large tank that algae seems to love.