I'm interested in collecting rain water to use for my hydro setup. My tap water is actually pretty decent - usually ppms <50 and ph ~7 ish - but I use a lot and figure rain is free so I might as well use it. Any tips on how to prepare it for use in an ebb & flow hydro system? Does it need to be filtered in any way? Additives? Can I just run it through a screen and pour it right into my reservoir?