[bluespotjawfish]

In theory, this program is Vista compatible (I asked that question before I installed it).

I just installed the keyspan and got the latest driver (for vista) two weeks ago.

Your pH calibration logic sounds logical to me. If the power went out and you had stuff tied to the pH level, bad things could happen to your tank if it didn't stay stored in the controller. Battery, hum... Any one know if there is a way to check if it is a dead battery other than to open it up and replace it? The data log goes away if the power goes off. I learned that earlier in this week when my daughter thought it would be fun to test my battery backup survival air pumps I have on my tanks. She plugged her heater into the same circuit as my aquarium with all my MHs running. So is that normal? If not, then I would say battery problem.