ra pissed man i wish i found this grow sooner, i think i could of helped.
btw the slime you get in the water and over your lines when using bennies with tap water is perfectly fine and will not harm your roots at all.
i think you tried cramming too much into one area tbh, i would say1-2 maybe 3 plants in there max....that slh should have filled that space alone easy.
i think the water cleanser your using is not helping your ph, you should be able to set your buckets and leave them for a week, not checking ph alll the time etc...
better luck next time man!
p.s not ragging on ya just pointing some shit out!