I´m a newbie and have been reading a lot about this all, and I have a plan for a small system in my garage under a grow light.  Few things I haven't found an answer to on the forums/internet (may its there, but I can't find it). 1. When thinking about size of system in terms of stability of it (pH/temp fluctuations etc) does one add the volumes of both the fish tank and the sump tank (that is - t…