Question about PH and runoff

Water going in is @ 6.5
Coming out @ 5.9- 5.7.
Is that about right?
I only have a Ph/temp tester.

Runoff coming out should be ~6.5 for a soil grow. If the runoff pH has dipped it probably means you have some salt buildup in your soil (assuming it’s a mature plant that has been fed nutes at least a few times.)

5.7 will be a challenge to get to 6.5 just with pH up. It may be time for a flush. A flush should bring it back to ~6.5.

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That’s been pretty normal when using ocean forest and big rootz soils.

What’s the plant telling you, dose she look nice and healthy? If so I wouldn’t worry about runoff numbers, keep 6.5 in and don’t stress to much. Like Midwest said, if your feeding salt based nutrients and tanked your ph by over feeding,that’s a different story, although the plant would be showing leaf issues.

I’m getting some yellowing leaves.

I read something that said the brown spots could be calcium deficiency or possibly nute lock.

Thank you

I too have similar readings of runoff: pH 5.74 and 5.33 from two Autos. Neither of which have any signs of discoloration on the leaves. However, on my next watering or feeding, I’ll be sure to pH-up a bit.
Now on to where I do see nutrient or mineral issues.
See below, from a separate posting of mine: To SCROG or not to SCROG Photos and Nutes.
I have VERY similar issues visible and was advised to use some Calcium & Magnesium; on it’s way to my door. I’ll be adding some later this week. I did not do a runoff test on these, but will later today and will try to post my pH readings for comparison. However, I’m not so trusting of my Vivosun pH meter/pen at this point. Just sayin’…