Bit different...

[spscrackhead]

Why not dose auto top off (low ph) into a calcium reactor?
I am not super good with chemistry but thought it was an interesting question none the less.

 

[P-Dub]

Good question. I am assuming that you are topping off automatically. So long as you still utilize a CaRx as it is supposed to be used but I think adding additional top off might not make much of a difference. The only issue I can see is battling the feed pressure of the CaRx and preventing backflow into the ATO reservoir when the top off pump is not used. I think it might be over complicating things.