Hey, i didnt have time to read every post, but heres my 2 cents.
I have a 4 X 4 space and used a 400w for a while, probably 3 grows. After that , i wished i had bought a 600w. So my advice is to get at least a 600w for the 4X4 space. After that, id say go for hydro system. Ebb flow systems are...