I think your pH down to 6.0 might be an issue. I'd say, don't pH your water at all, or anything else, and see what happens. Also, you don't need to wrap tap on a container that is a soil grow. Blocking light is done on containers used in hydro to prevent algae from growing in the water, which will plug pumps and compete with roots for fertilizer. Is pHing to 6.0 something new? Have you done this before with good success?
Shovel, you really need to work on that shy personality.
Esteban, you must be a mad chemist!