hey prodaytrader i am useing 2 eb and flows with 15 gal in each res as well. The guy at the hydro store said to change water every week. Is he just trying to sell more neauts. I was planning to go like 3 weeks like you adding neauts and water of course as needed. Do you run a filter? I seem to have like a slight frothy foam in my res and some suspended solids of some kind. Is this normal? Water and neauts are about 4days old ph at 6 t0 6.5.:rasta: