Nice, glad it's working for you. If the pump shuts off it will siphon all your pH solution if the pump doesn't have an anti siphon valve?
Pump seems pretty big for dosing pH, but it was cheap.
As long as the pump is above the pH solution it will no siphon.
Yeah, the pump is really up to the user. Granted I picked this pump for my 140 gallon reserv. but it is holding a 5 gallon bucket perfectly. So even though it is 3.5 GPH it isnt over dosing.
Remember you can dilute your pH solution too. I use the powder so I can tweak the strength of the solution to how ever I need it.
But you can buy a Peristaltic Pump. I just didnt see the need in doing so, they cost more. As long as it is AC powered, you will be okay.