Yellowing, Burnt Leaves, Slow Growth

This is my first grow and aside from sprouting the seeds, things have not gone well. I'm running RDWC indoors under three 240W LEDs 16" above the plants in rapid rooters in hydroton. Room temps have been 67 to 77 and the res temp as been 69 to 72. PH been 5.8 - 5.9 steady with 620 PPM (220 out of the tap).

Keep in mind that I had to completely drain and clean my res due to a slime infestation and root rot due to room/res temperature issues I now have under control. So three days ago these plants were soaked in 0.5% H202 and I had to "repot" them so I could soak they hydroton in 3% H202. Several of the plants had decent roots while others had nothing outside of the rapid rooter due to root rot.



The "repotting" triggered the yellowing and dying of the older, big leaves. Most of the plants are now putting out new leaves. My concern is that I'm still seeing some browning on the tips of the new leaves. My tap water is 220 PPM and I'm currently at 620 PPM so 400 PPM is from nutes -- GH Lucas formula initially 1/4 and I've since diluted with RH. Since these are now 3+ weeks old, should I increase the nutes or am I still getting nute burn and need to back them off?

Thanks in advance guys. I've read that most people just start from scratch after they get root rot but I'd like to try and save these so I can verify that I have things running properly in my room now without wasting another set of seeds.

In case anyone's interested, my room temp issues were due to having to run the heater for the first time this year which exposed a serious flaw in my ventilation design. I was also using foggers which I now realized put off a ton of heat in the res. I was only bubbling in the control bucket and relying on the foggers to create the mist. I've now removed the foggers, bought a pond air pump with three 14" stones in each container which has the water "boiling." I also put in a DIY evaporative cooler that's keeping the res temps lower them room temp.

I dont care for the Lucas formula. That may be N deficiant, not burned. You should be using veg nutes instead of flower nutes like Lucas says. Those are 3 weeks old? Im sorry. Root rot is terrible. You can save them, just be patient. Hygrozyme may help also.

Don't bother saving them. Start all over. Don't use any nutrients until you get to the 4th node. These are trashed and burned. Seriously...ZERO PPM until AT LEAST the third node, 4th will work too and JUST start showing signs of deficiency. The seed contains plenty.

If my tap water is 220 PPM with at least 100 PPM CA, is it still usable or would I be giving my plants nute burn just from that? I didnt' install an RO system in my room (my initial tap reading was 115 when I was planning) and it's pretty crowded as it is. I could put one in pretty easily but don't have anywhere to keep the RO water. I have an RO system in the kitchen but it only holds like 2.5 gallons at a time.

Tap water could be your problem, but 200ppm is pretty law. Should be safe. I use RO personally, but in most areas water straight off the tap is fine.

It's not the tap my tap is 200 too
Did you start'em using 400 ppms
of nutes? This would be on the
HIGH side for seedlings, 200-250
after 7 days of plain water first
is how I start'em in nuteless dirts~

MGG, is that 400 including the tap PPM or in addition to?