C02 rx questions.......

[SuperFudge]

A Reactor will produce a higher alk at a higher co2 bubble count, rather than a higher effluent rate.

A reactor is also not the best way to raise Alk, it is better at maintaining alk and raising calcium.
Depending on how low your alk is and how high your Ca is, It might be better to raise it with an alk buffer, then dial it in to maintain it.

I wouldnt worry at all about the effects of ph dropping at all, you would almost have to try, to really drop ph.
As your alk raises, it also is helping to prevent a drop in ph.

If you just keep the effluent line above the water level to let exess co2 burp out into the air, youll be just fine.