I have a 150 gallon stock tank in my duck's pen (they get locked in the pen at night, and free range the yard all day.) The ducks sleep in the "pond", and they go bob around in it sometimes during the day. There are concrete blocks that work as steps up into it, and twice a day for five minutes, a hose on a timer that's at the bottom of the tank runs into the tank, and as the water rises, it drains out of overflow holes I drilled into the top, down the rubber hoses in it and into two raised beds I use to grow veggies. Once a week, I pull the bung at the bottom and drain the whole thing through a pipe over to some fruit trees. It works pretty well. The water never looks AWESOME and I wouldn't make lemonade out of it, but it's not foul.