We have a former wallow - basically a giant hole about 2 feet deep, 6 feet across, 5 feet wide, that the pigs dug to lay in the mud. Between the huge amount of rain and snowmelt it's basically turned into its own tiny pond. The ducks love it, since the pigs don't go there anymore as we downsized and they're in a different area. However, the water is a NASTY green and it bubbles in the sun. It doesn't stink, but it sure looks gross! They swim in it every day and drink the water. I just want to know if this is safe for the ducks (health wise). It's probably a massive cesspool of bacteria by now. If bad, what can we add to the water to make it safer/cleaner? It doesn't look like it's going to dry up any time soon (or ever), so any ideas would be good. The weather varies from 50 degrees at night to 90 in the day.