Happy Frog soil issues

Well in soil a meter isn't quite as critical.....if you can get by with strips or drops you could do that. But in your case I believe the issue is your very alkaline water. But yes, nothing beats a good quality ph meter that is calibrated often.

Bob, I honestly use the soils I mentioned BECAUSE I don't have to worry about ph issues. ANY plant's ph will lower in older soil after time so you either need to flush or transplant.

As long as you are careful, I personally have transplanted plants 6 weeks into flower (because that's when the ph issues became most apparent) and let the soils do most of the work buffering ph. It's easier to transplant than flush....but not always possible to do. Imo, the age of the plant doesn't matter for transplant as long as you are careful.

That all makes total sense. As for the transplanting at this stage, I read some info on it but the only part I'm missing is how do you seperate the roots from the old soil and not break off large amount of roots? or is just putting the existing plant (soil and all) into a larger pot filled with new soil sufficient?

If you have room to go larger....then do the second one. As far along as your girls are the less you mess with the roots the better. If some old soil falls off great but don't yank anything. Be gentle with the roots and old soil and give them a day or two to realize they've got more room and you should see a positive result.......especiallly if you switch to RO water and make sure everything goes into your pot at the correct ph.

Top dress the soil with lime 10.37ml/L of soil. Adding lime will take about 2 weeks too start working (you don't have that long) Also next time you water add lime too the water, the lime with the water added too it will start working too fix the pH immediately, this will bring you Ph back in too check with out the stress of having too re-pot.