Yellowing leaves,dark spots

[MesaBoogie]

Hi, sorry for the late response, Canada day weekend

I use litmus paper to check ph of water and accurate 8 in soil. In soil it seems to be a steady 6.8.. Not sure if my AC8 is correct or if that's just the way the sunshine mix buffers out. I put about 6.3-6.6 ph water in. I have not checked my TDS meter yet. But I think it's within a reasonable range of accuracy. Since I've got the pen, my tap water has always been a steady 300ish ppm.

The nutrients I am using are all from a local hydro store, Jakes Fertilizers. Not really much information on the net about them. It's a 3 part series. Grow, Micro, and Bloom.

Grow:2-1-6 Bloom:0-5-4 (pics of ingredients and recommended dosages in photo's on page 2)
The Frequency is supposed to be Water, Water, Feed. I have found that the plants seem to prefer half feeds every other water. Gives them 1 feed per week. The spots are no longer progressing. But I'm getting a lot of yellowing for week 8 of flowering.

Thank you guys ! @Waira @GoAuto6 @MedCzech

 

[Waira]

great on the A8 unit! I did a slurry test against the A8, and they were withing 0.2 of each other, so the A8 is just fine,.... at 6.8, it's a bit high, expected in that hard water,.. a lot of CaCO3 going in which can start to mess with both uptake of certain nutes and pH elevation, resistance to lowering in-pot pH,... the yellowing looks P related, a co-symptom not listed that i see, but it occurs so often with the usual P defc. necrosis, that it's not coincidence IMO,... some of it could be minor N defc., part of the normal fan fading at this stage,... they elevating your Bloom more,.. and consider using a bloom booster in the future (high PK product),....