okay here is the thing. I have rain barrels that supply about 80% of my water for my gardens. I want to take this a step further and collect rain water to substise my water for my animals, and duck pond. Has anyone every tried this? I am sure the water for the aniamls to drink will need to be filtered as well as have a much larger storage tank then my little rain barrels. I know you can buy really $ cistern systems , but I am looking to build my own if possible. Any hints, tips, ideas?