Runoff pH still climbing!

I would be tempted to follow the advice from @growinggrannie. If your medium is soil then you shouldn't be watering with such low pH. I get your trying to lower your soil ph but it could cause ph lock outs. So if its soil put 3 times the amount of water through the soil, catch samples of runoff periodically while your doing it. Before you put the last bit of water through your runoff ph should be in range. Aim for ph 6.2 with the water going through.

Looking at your diary, seeing what you're trying to accomplish, I think you're going to have to do a couple of things: first is to do a hard flush which, given that you're growing in 3gallon pots, means running 9 gallons of pH'd water through each pot (keep checking your runoff - it'll come down). The second thing you're going to need to do is to cut the amount of BioGrow you're giving her... this has too much nitrogen in it for plants in the flowering stage, especially at the rate you're feeding it... An excess of nitrogen will cause a lockout of other vital nutrients resulting in the red stems and the yellowing/discoloration in the leaves. It means that no matter how much calmag you give your plants, they're unable to absorb it - pH also has a lot to do with how or IF the plant can absorb the crucial nutrients as well - aim for a range of 6.0-6.5 in soil... Once you've flushed, the first feeding (after she's dried out) should be 1/2 strength. Good luck! Looks like a really nice harvest is in your future!!