reactors

[BlueAbyss]

Am I to assume that you are already running a calcium reactor? If so, I would run the effluent from that through your media in the second reactor, just to grab the last little bit of carbonic acid from the water. Short of that, simply running your tank water through any calcium media will add 'some' buffering capacity against low pH... but not much, and you run the risk of it becoming a biological filter.

I once assumed that doing something like this would help maintain pH... after all, the ocean stays relatively constant and it's full of aragonite. Unfortunately, chemical mechanics in a tank are a little different than the ocean