My design has two tubs that drain by waterfall back into a central reservoir...I'm wondering if the entire Res must be covered/lightproof??? I will be using Foxfarm Grow Big, Big Bloom, and Tiger Bloom.... My water is from the tap. PH7.8 and using a TDS my baseline PPM is 700... I'm not sure how bad that is.. After soaking my Hydroton in PH5.6 water for a couple days and it still seems to be raising the PH by 1 point per day...

Still waiting on germination.