i've been dipping them in 2.5tsp 4% hydrogen peroxide/gal every morning, as well as giving the roots a good rinse.
inside the netcup is clay pebbles, or as you call them hydroton, yes.
the net pot is getting caught by the rim of the cup as it's 3in, and it has a small airspace, then water at the bottom of the cup that the roots drink up.
click here for a better explanation
i don't know what you mean by hand feeding, and if i put drainholes in my cup the water would leak out and the roots would dry out then die. so no drain holes lol.
how can it be overwatered in hydro and are you sure there isnt a cal problem?? i'm 99.99% sure that's what it is, foxfarm's lineup contains little to no cal, and i don't really have a liable cal source atm, so it just makes sense to me.
if i fed at 1/4th stregnth my plants would perish from starvation, the salts build up at the bottom of the water, which is why i think i have to feed so much.
i'll start using bottled water instead of tap.