Roots are probably just stained from that caca coloured water. IMO ppm is way higher than it needs to be. Are you sterilising the res at all? And what does the plant look like, if you have a root problem plant will be a tell tail sign
The feeding every other week might not be the right way, but I've always had good harvest and never had deficiencies. Main reason for it is that if you add nutes every refill the ppm gets ridiculously high. Especially since I just run tap water which is already at 350ppm. If you notice a...
I can't really comment on the nutrients, but should be fine as long as they aren't organic. I would run sterile instead of messing around with beneficial bacterias i.e great white and hydroguard
I do a res change before switching to flower and then every second week I refill with nutes, I never...
I just run 50% peroxide, 10ml once a week. As for DO, I haven't really noticed any differences in growth when res temps are considerably cooler. I say give it a crack without a chiller
I ran dwc through summer here without a chiller, grow room use to sit at about 30 degrees for most of the day. No root rot or green shit growing in my res. Should try running sterile before forking out for a chiller or ice probe, just my 2 cents
Will probably also want to fill your net pots with some clay pebbles or something and do what @go go kid said, otherwise you will get a rez full of green shit
I use to run a tight s coil of black poly pipe at the bottom of my res with tons of tiny holes in it, worked a treat. I've since moved to flumeing/waterfalls and haven't bothered with airpumps/stones since.