hello i'v been slowly learning how all this works, but i just made a diy sump, old 55 gal, and i seem to need to add 4 gallons of ro every 5-6 days. i have a 120 gallon dt and the sump holds about 30 gallons. thier is also a small 12 gallon frag tank who shares the same sump. my dt is not a...