markB I don't think this stepper motor would be strong enough to turn a ball valve. If so PLEASE LET US KNOW!! This would be a great and cheap mecanism.
I agree. You would need a gearbox, and then you may as well use an actuator, unless your're a mechanical wizz.
I looked at automating a 1 inch ball valve and it got too hard, thats why I started on the gate valve idea.
Sorry no cheap solution...
Those pumps look like a great idea. Far better than adding a VFD.
Thanks for the PH probe link, they do seem a little cheap, but maybe they work fine for a year or more.
Mark