I recently started ebb & flow with 2 gallon pots of promix/perlite 50/50, I only flood about 1/3 way up the pot but 10 minutes later the top is moist. None of the mix gets into my rez when it drains since the cycle is slow enough, maybe 10 minutes. I only flood them every few days as it takes a while for them to use it. This is just for veg while the pots are close together, later when I spread them out in my bloom system then they get top feed via tubes, just since it's too large an area to ebb & flow.