Our horses are pretty picky on drinking, so bleach made them quit drinking from the troughs for a while. A COTH tip was clean the troughs using the power washer. We do that with plain water and the troughs look great, no one quits drinking. Stays nice for a couple weeks before the alge is back in summer heat.
I took the two troughs to the car wash the first couple times, to see how the method worked. Had to chase one I did not set next to a wall! Ha ha. Entertaining for the folks washing cars! I did rinse troughs again at home with clean water, to insure there was no car wash residue. We ended up buying a power washer, so now I can wash them at home.