First time grower, the hydro venture please help!!

So this is the first run at growing and using DWC no less, two clones, Candy Cane, and White Widow. At first I didn’t have a pH meter so had to rely on phenol drops, horrible idea. pH ended sitting for about two days at 3.7! I quickly prepared the next solution of nutes then switched the res. I used the 0-4-8 Lucas formula with an additional 3.5tsp of cal-mag and silica blast as I have a seven gallon res. The final pH was sitting at 5.4 and ppm at 520 (R/O water @ 005 ppm used).
Current nute solution is at 5.8 pH 450 ppm same amount except I forgot to add a final tsp of something, can’t remember what ..Also a 1000 watt mh light is being used that is 18” away from the youngins. The temp gets a bit on the hotter side at around 85-93 degrees F, RH gets low as well at 20 although I’ve been managing about 30 with the humidifier that was added.
The CC hasn’t grown at all in the 5 days. No new leaves have sprouted or anything, and on 5/5 one of the leaves began to turn a slight yellow. Today 5/7 @1 am the leaf seem to be slightly more yellow. The NL on the other hand has about 2 days of great growth when I had first changed the reservoir and added properly mixed nutrients, growth appears to have stunted slowly.
I recently changed the reservoir again and something seems to have gone wrong although I used the same amount of nutes. One of the leaves has a slight brown spot on the edge of the leaf, red/purple stem with white all over on the upper parts of the stalk, any ideas? All and any help is appreciated, thanksView attachment 2646194View attachment 2646195

Do your clones have roots?

Yeah, they both have roots and were in rw cubes. If I take out the net pots I can see the roots to the NL pretty well but the CC I Cant.

What's your water temp?

It fluctuates as I'm not always available to add water bottles but usually around 70. I just checked on them though and both have roots that shot out over night and are now sticking out the net pot. I'm not sure if me lowering the water level may have aided?

yes it did the bubbles do the work!!

its easy to get lazy with dwc but if you can keep lowering the water the roots will continue to search for the res.

obv the roots do great in the water but the bubbles splashing the roots with nutes allows maximum air into the roots!

Awesome, right now the water is probably at 1/2" up on the net pots with bubbles splashing each pot. Only thing still bothering me though is the leaf got slightly more yellow on the candycane. But it still did shoot out roots over night, so would it be okay to presume it may be on its way to recovery? Thanks for the assistance, much obliged to all.

New roots pretty much mean they are growing/recovering. I think it takes 2-3 days for deficiencies to stop once you correct them... just like it takes a couple days for them to show up.

All right awesome, thanks for the help. The pH has stabilized and the roots are growing vigorously. Although the candy cane hasn't grown leaves it has roots that grew a good inch and a half since yesterday evening. The NL now has multiple roots growing out the pot and they are getting closer to two inches exposed from the pot!