My old probe was reading a solid 1.00 pH, I recalibrated and it read fine for a few days and then returned to 1.00. I changed the probe and recalibrated, read fine and now 1.00 again. Is my controller haveing issues?

Does it give you wrong values for temperature or any other parameter too?

All the rest of the values look correct. I verified the temps change when I pull them out of the water.

Then it could be the controller board may have gone bad for some reason. If you want to send it back to be checked out, send me a pm.