Need ideas..pond/pool

[SamG347]

I got a 50 gallon stock tank tonight at work and a drain to install on it. Going to just use this for the ducks...should be great!

 

[TLWR]

My 3 runners just graduated to a larger kiddie pool and they spent pretty much the entire day IN it and it is kind of nasty already. I'd love to make it just a week without having to change the water.