Tuning a calcium reactor

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A quick question, I am setting up my new calcium reactor. It is a Barr Aquatics recirculating model with 2 chambers.

I have a pH probe in the first chamber, what pH am I aiming for, I think it is around 7 or a bit less, is that correct? Right now the pH in the first chamber is 7.30 and I have been gradually increasing the bubble count once a day to adjust it.