HELP! Help diagnose my DWC indoor plant issue!

Hi everyone,

First time poster, first time with DWC. I have grown successfully in soil before. I have been completely overwhelmed by the many, many different opinions and techniques available for DWC. I need to reach out directly! Sorry for the long post but I really want to get this resolved. I’ll attach pics, describe my setup and hopefully find some answers.

Room
4x2x6 tent in a closet,vents into the hallway
ac infinity t4 (Temp 76-78, 82 max)
humidifier going on low 24/7 to keep room at 60% RH and stimulate the fan to turn on
5 gallon buckets painted black (temperatures range from 68-73 depending on status of ice bottles inside buckets)
4 hose air pump with 2 hose/2 air stones per bucket
net pots with hydroton that was soaked in pH=5.5, ppm=300 (distilled water, dilute CaliMagic, dilute Flora Trio series)
the bedroom has an AC unit attached to window that is constantly filling the room with fresh air that is modified by the conditions inside the tent
Phlizon Linear Series PH-2000 SMD LED light (dimmed all the way down, 240 watt, 24" distance)

Plants & Nutrients
Distilled water that is EC=0 and ppm(0.5)=3-5
pH between 5.7-6.0 (at various times throughout this tale)
two feminized white widow from canuk seeds sprouted in rockwool soaked in pH=5.5, 200 ppm water
CaliMagic
Flora Trio (micro,gro,bloom)
Miicrobial Mass (intentional double ii, it’s a beneficial bacteria product sold in Canada with 5 different Bacillus species and a surfactant)

So far I have used the Flora Trio in 1:1:1 ratio. I started the plants with 25% strength nutrients. I recently transitioned them to 50% strength. My fear is that I am under-feeding. I have read many tales of people that under-feed or do their entire grow 400-600 ppm. I initially made the mistake with these plants of cutting the CaliMagic concentration to 50% the entire time even though I have distilled water rather than tap water. I tested this (just recently) and 1/2 strength is ppm=150 while 100% strength is about 250-300. So, that was one of my main problems. I am currently giving 100% CaliMagic while still only giving the plants 75% strength of the Flora Trio nutrients. This entire time I have not been topping up the water, that may play a part.

I will give a brief timeline of events/measurements to go with the pictures:

May 07 Setup the DWC buckets with 500 ppm, EC=0.8 water (50% conc. of CaliMagic and 25% conc. Trio), placed seedling in rockwool cube onto layer of hydroton in net pot. Water was touching the very bottom layer of clay pellets.
May 08-May 12 Plants growing normally, still can’t see roots protruding anywhere. Lower water level right to bottom of net pot instead. Noticed that even though roots are not in water, the EC, ppm and pH all increase overnight .
May 13-14 Still can’t see roots, pH stayed at 5.7 for a few days, EC and PPM stayed stable
May 15 Both plants finally showed roots. At this point, I still haven’t changed the water and the ppm & EC steadily slowly rise over time (probably evaporation?) while the pH would increase from 5.7 to 5.8-5.9 every 24 hours and I would pH it back down to 5.7.
May 17 Brown spots on plant 02 are getting worse but not spreading (see pictures), otherwise the plants looked good, roots grew, plants grew tight nodes. Colors all looked great. Spots were diagnosed as ‘nutrient splash’ on another site. Was advised to lower the pH=5.5, EC & ppm stable . pH still rising from 5.5 to 5.8 overnight.
May 18 Last day that pH shot up to 5.8. It stabilized at 5.6 and then drifted within range til May 22
May 19-22 Started measuring water level in buckets using measuring stick ( should have done this earlier). Plant 02 brown spots have not spread at all and it looks like it’s growing fine (see pics). pH seemed stable and I ‘let it ride’. It took two days to go from pH=5.5 to pH=5.8 so I thought this was a good sign. I was then advised to increase the pH to 6.0 because that’s where my plants seemed to want to be and it’s within the range of absorption for hydro.

FIRST BUCKET WATER CHANGE

May 23 First water change, which is where my mistakes started. I was still using 50% CaliMagic but now 60% Flora Trio recommendations. This increased to 580 ppm, EC=1.2, pH=6.0. Yes, this is scary to me because I let the bucket sit for 16 days but the pH and ppm were relatively stable during this time. I let the pH ‘drift’ and it slowly started going down. ppm are relatively stable until the next water change.
May 24 Noticed leaf curling on plant 01 which has still never gone away but NO OTHER symptoms, looks different than plant 02.
May 26-28 Plant 01 still minor leaf curl, no other symptoms (see pictures). Plant 02 develops more and more rust spots (see pictures). Bottom leaves become brittle. Leaf damage starts to affect newer but not the newest growth (see pictures). May 28th I realized that I needed 100% CaliMagic so I added it to nutrient solution without making a fresh bucket. This was probably another mistake but the roots started growing again within 24 hours so I figured that this was a good sign!
May 29 Plant 01 is the same. Plant 02 oldest leaves are looking even worse. The plants seem to be drinking though.

SECOND BUCKET WATER CHANGE

May 30 Changed bucket nutrients to 100% CaliMagic and 75% Flora Trio. It is now EC = 1.3, ppm = 665, pH = 5.8
May 31 Now, based upon my measurements, the plants seem to be drinking but the pH is now dropping rapidly (from 5.9 to 5.6 every 8-9 hours). Plant 01 is still slightly leaf curled and plant 2 rust spots seem to be spreading. I’ve attached the most recent measurements for this phase. Please pay attention to the dates/times at the top of the measurements. Towards the end I have been checking them very frequently to see how it’s handling the new bucket.

Things to know

  1. The plant with the brown, dry dead lower leaves is the younger plant by about 3 days.
  2. The plant with the upwards leaf curl sits closer to the humidifier (but there’s a fan dispersing humidity).
  3. One plant only have leaf curl and the other has dying leaves at bottom of plant.
  4. Both getting the same nutrients and they both treat the nutrients essentially the same (all measurements for each variable always change in the same direction with some variation)
  5. I run two air hose per bucket with 2 air stones (too much O2/CO2 ??)
  6. I never “top up” the buckets with fresh water because I can’t figure out what kind of water it should be (same as base, more dilute, less dilute, just calimagic, etc.?) This might be my big problem as well.

I was planning on doing some more LST and topping once more to get 4-6 growth tips per side and then making a canopy. I have two fresh seedlings ready to go… should I scrap this grow or can this one be fixed still? Thanks in advance. If you need more pics/info please let me know!!!

week 4 measurements