oooooorrrr if you want serious water storage for animal drinking storage and you dont want it to go yukky, buy a black 1000l ibc which is a large plastic container held in a metal framework, has different types of taps on the bottom and large filler on top. they must be properly cleaned before use and its a good idea if you can find out whats been in it. you can mount this in a trailer or pallets or on the floor. weve just bought one from ebay and collected it myself to save hi postage cost. £50.00 for black ones that are as good as new. this will solve problem of no permanent water trough in cattle field..............these have lots of applications for the smallholder....................neil