So I just bought a gently used 1200 GPH pump for $18 from a guy selling off all his fish equipment. I've been wanting to build my own W/D sump for a while and now I have the piece that was going to cost me a lot of money. Trouble is I was just going to start out with a 10 gallon DIY with a 5 Gallon bucket. I may be wrong but I think this pump would be too much for such a small sump.
So my questions is, how big of a sump would I need to be able to use this 1200 GPH pump?