@NewOfficialDrillInvaders, I always used a nutradip pH Probe submerged in the water with a external digital read out of the pH. At any given time i can pop my head in the door and see the green digital real-time read of the current pH. And because it is a circulating system, i just drop some pH down near the pump intake and it sucks it through and distributes it around the system. Couldn't be easier.
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