Fight, Start over, Give up

[gardenmark]

Well I didn't understand why some growers change the nut. once a week and why some just top off? I didn't understand that growing hydro was harder with organic nut. I had six different fish tank heater short out and stop working, not good for ebb and flow and temps in the greenhouse down to 40F at night and 82 every day w/ sun. I was using Hydrogen peroxide but not enough w/ 75 gal tanks. I was warned about used equipment and I washed the tanks and trays and net pots w/ hot water and bleach, I didn't understand I needed to let them soak. The lettuce tray was the first but tomato tray and now the pea tray are showing sign of root rot, I'm sure I was the cause of cross contamination. The trays were covered w/ panda film to keep out light but maybe not enough air movement in roots?
My main question is this worth fighting to save the tomato plant and pea plants, roots just showing black tips, not like lettuce all black/brown. Or should I move every thing out and just start over, may be w/ salts, after I bleach every thing including floor? Or may be give up on ebb and flow and go drip?