Tom, Welcome to AA!
I agree that a pH controller is a nice gadget, and if your budget allows for it, by all means get one.
But if money is an object, be aware its not exactly a necessary gadget. It depends a lot on how much buffering capacity your water has.
For example, I have 10dKh of carbonate hardness....plenty of buffering. I run my CO2
24/7 without problems. I do use more CO2
this way, and if I had an inclination, I could hook up my solenoid to a lamp timer and run it half as much.
But, if I had 3dKh, I'd barely have enough buffering for safe CO2
injection, in which case a pH controller would be a very wise investment.
I'll also state that any good CO2
regulator, like a Milwaukee or JBJ, is not going to give you and end of tank dump. Both units are built well, and the needle valve is the primary reason you won't get a tank dump.
Tank dumps usually happen on a regulator only setup...the cylinder gets too low to apply enough pressure ont he regulator valve, and it starts rapidly burping, which release way more CO2
The needle valve actually will slow CO2
rate as the cylinder goes empty, because it has less gas pushing against the valve.
I've tried to induce a tank dump with my milwaukee once, and I couldn't get it to happen.