Samoa Kush DWC with Electric Sky ES300

This is the week where I began to experience some hard lessons in DWC, particularly since I pulled this together DIY. I noticed slow growth on the #4 pheno and then popped the hood on the rez to find some browning of the roots. Since this was my first time doing DWC, I did a lot of reading. I attempted to block light from getting into the rez to see if this would help resolve. Day 15 -8am: ppm 350, PH 6.2 -Calcium deficiency identified. Increased CalMag with rez change. 7g @ 530ppm, PH 5.8 Day 16 -8am: ppm 515, ph 6.2. Corrected ph to 5.6. -9pm: ppm 525, PH 6.0. PH corrected to 5.5 @ 520ppm -11pm: ppm 510, ph 5.6. Day 17 -8am: ppm 505, PH 5.8 -Added 1g 1/2 strength nutes at 530ppm, ph 5.7, Added hydroguard -Root rot noticed. Full cleaning of rez. Soaked plants in water with hydroguard. Cleaned and sanitized rez. -New rez 7g @ 517ppm, ph 5.9, Calmag @ 1/2tsp/g, Topped off rez to raise water level. Added 4.75g. New ppm 505, new PH 5.9. -10pm: ph 6.1. Corrected to 5.9 @ 490ppm. Added 1g nutes @ 495ppm, PH 5.6 Day 18 -8am: ppm 504, PH 6.0. Added 2g 1/2 strength nutes @ 484ppm, PH 5.7. -5pm: ppm 495, PH 5.9. Added 1g water to correct PH to 5.8 and reduce ppm to 470. Day 19 -12am: ppm 478, PH 6.0 - 10am: ppm 459, PH 6.0 -4:20pm: ppm 457, PH 6.1. Corrected to 5.7PH @ 457ppm -9:30pm: ppm 455, PH 5.9. Removed 1g of water to reduce water level Day 20 -11am: ppm 437, PH 6.0. Corrected PH to 5.8 @ 438ppm -Fimmed all tops -7pm: ppm 438, PH 5.9; Added 1g water at415ppm, PH 5.7. -10pm: ppm 404, PH 5.9 Day 21 -8am: ppm 389, PH 6.0. Corrected PH to 5.9, not sure why lol - 7pm: ppm 374, ph 5.9