Indoor A question about soil ph and runoff?

[Haunts]

With previous grows Ive never checked my ph before because I read that soil acted like a buffer but I thought I would give it a try. At the start of my grow the pH of my water with nutrients was 6.6 going in and the run off was about 6.3 so I thought thats all good, I won't bother checking it again.
I'm about 2 weeks from finishing now but about a week ago my lower leaves started to yellow and started to get brown spots. So I started adding some cal/mag but it hasn't seemed to have helped. Now I've just checked my ph with nutes and again it's 6.6 going in but the runoff is down to 5.3. I'm guessing this is my problem? Does soil lose its buffer over the period of the grow?

 

[namvet25]

With two weeks left some leaves especially lower ones will turn yellow and this is normal.If your using organic nutes there is no need to ph but if you use chem nutes you should always ph your water.I wouldn't worry about runoff at this stage because you should start flushing soon.

 

[Haunts]

Ok thanks, I do use organic nutes.

 

[HubbaBubba]

With previous grows Ive never checked my ph before because I read that soil acted like a buffer but I thought I would give it a try. At the start of my grow the pH of my water with nutrients was 6.6 going in and the run off was about 6.3 so I thought thats all good, I won't bother checking it again.
I'm about 2 weeks from finishing now but about a week ago my lower leaves started to yellow and started to get brown spots. So I started adding some cal/mag but it hasn't seemed to have helped. Now I've just checked my ph with nutes and again it's 6.6 going in but the runoff is down to 5.3. I'm guessing this is my problem? Does soil lose its buffer over the period of the grow?

I flushed my soil heavily and it seemed to lose its buffer. Not just watering until runoff, full flushing.