Yea!
Now that the coffee has kicked in, that obsevation about the 2 poly lines sounds right!
Thanks for the insight. Do you usually return the effluent with dosing pump or is it a slow drip with a valve back to the sump or the tank?
I imagine if you want to get real fancy you could use a pH controller and solenoid.
$$$
But in most cases, what system are people with DIY Calcium Reactors using?