pH Problems during early flowering

[Dalek]

I'm currently on my 3rd indoor grow. I'm having the same problem as I did on all 3. First 6 weeks, they look great, then leaves begin to yellow. I recognized signs of low pH and began watering and feeding with pH 7.0, the runoff was 6.3. I spend a lot of time measuring pH but after seeing pictures, Sirius told me after seeing pictures that it's definitely pH and even though my runoff measures within the 6.0 to 7.0 range, the pH around the roots is probably 5.3.

I took the Master Class, and went through it several times and I didn't see anything that would prepare me for this. So, today I'm going to increase the water to 7.5 and see if this raises the pH at the roots. I'm using Happy Frog soil, and General Hydro Trio. I've been following Nebulas watering and feeding guides. I'm not sure what to do.

Help! (Please!)

Dale

[golfnrl]

Hello Dalek welcome aboard! PH problems are frustrating for sure. When you water and check the runoff PH do you check each pot, or just the one in question? How are you measuring the PH? Is your equipment calibrated? Can you put up some pics please? As a Master Class grad myself I do not want to or mean to insult you with basic questions...

[Dalek]

Hello,

Thank you for responding! This is my 3rd indoor grow in a 5 X 5 tent, HLG750R, AC Infinity controller.I use an Apera tester and calibrate it monthly. I,m using Happy Frog Soil and Gen Hydro Trio.

I began each grow with the plants looking beautiful up until about week 6.Then they begin to fade in color, and just look sick. . I've been discussing this problem with Sirius by him explaining the difference between runoff measurements and the actual pH at the root zone. This morning I fed with pH 7.4, runoff 6.0 so I have a way to go. My next watering will be 7.8. I think I'm on the right track?

Dale