pH of Ca reactor with ARM media?
 

What do people set their ph of their effluent on the reactors with Caribsea ARM? I'm reading on the container that its recommending the reactors are set to 7.5 but i'm reading most people setting it to between 6.5 to 6.9. Which one is it?

6.7

6.7-6.8, However I think it's more important that the effluent alkalinity be approx 3x your required value. ie 10 dkh (tank), 30 dkh (ca effluent).

I have yet to figure out why that matters if the end result in the tank is fine. (8.2) Can someone explain?

Because it must be low enough to dissolve the media to produce sufficient calcium. Of course this all depends on reactor design and calcium demand.