my hydro system (deep flow)
 

Dear Ron, my hydro system (deep flow) for cannabis is off to a good start. just a couple of questions to keep it going smoothly. I have 3inch pvc pipes with a continuous flow of water circulating (no timer). the plants are growing in 1 inch rubber holes cut to 3inches. the roots are always under water in this system. my plants are about 10inches and look ok. some of the lower leaves have little orange/brown spots on them. how do i fix this? I'm switching to a proper hydro solution (currently using Miracle grow) i know this isn't recommended. what's best for cannabis and where can i get it easily? i know the deep flow isn't highly recommended by anyone. my system seems to be going ok but I'm still worried about those damn roots always being under water. my friend says I'm nuts, and that an airstone will work just fine. what do you think? as always thanks for sharing your ideas and tips. Enjoy the holidays, thanks you are the man.

What you have there is an NFT system. Nothing wrong with that. Just make sure theirs plenty of oxygen in the water and that the water is flowing at a good rate.
Yes I would say those spots are from Miracle-Gro. Switch soon to real hydro solution for best results.