Hi, I’m still relatively new to growing (7th or 8th grow) and have been having an issue I can’t solve. First, let me give you some background on what I am running.

I'm running two plants at a time in a 2x4 AC infinity tent.

Plants in the picture are a Hubbabubbasmellascope x sky stomper 2.0 & a sky stomper 2.0

Genetics: Mephisto
Lights: Two IONBOARD S24 220W Full Spectrum LED
Soil: Coco Loco
Nutrients: Mega Crop 2 part
Water: RO Water with CaliMagic Cal Mag, and Phd
Temps: Mid 70s to low 80s
Humidity: Keep within the range of the growth stage
DLI: Keep within range for the growth stage
TDS: Start feeding week 3 around 300 PPM, scale up to around a max of 650 in full flower
PH: Try to keep around 6.00 but let swing between 5.5 - 6.5
Watering style: Bottom watering using 6-gallon Octopots.
Measuring tools: Apera pH and TDS, Photoone on iPhone for DLI

Issue: The plants start strong and look really healthy, then around the time they hit the stretch, week 4-5, it seems like they get Ph lockout or something like that. Additionally, at some point, the pH appears to get stuck at a specific number in the tank, say 6.3, and pH down will not lower it. Then it gradually rises.

Last grow: I realized I was using the wrong kind of cal mag, was using TPS, and didn’t know that type wouldn’t work. I also learned that if I top water 2 or 3 times the pot's volume, the stuck ph issues are resolved.

This grow: I used CaliMagic Cal Mag, top watered at 3x the pot volume in week 3, and it still ran into Ph Lockout and the Ph getting stuck a week later.  I had to top water both plants again this past week to unstick the pH issue.

Any suggestions on what I need to change?


Troubleshooting suspected pH lockout issue