My new, expensive, electronic pH meter died last night. After 3 consecutive readings that indicated my reservoir pH was too high, it occurred to me that I might need to recalibrate. When I did, the meter reading started at 7.6 and then slowly climbed to 16 and then the meter quit working.

Unfortunately, before I caught on to the fact that there might be a problem, I added a significant amount of pH Down to my res. I suspect that reservoir pH is now way too low - possibly as low as 3.5 - although I won't know for sure until I get a new meter in a couple of hours when the hydro store opens. Oh, and just to make things more complicated I started the plants on 12/12 lighting two days ago. And of course, the dark period takes place during the day. The lights won't go on until 7:30 tonight.

So, I can wait until tonight to check the pH or I can interrupt the dark cycle and check as soon as I get home from the store. If things check out, then the lights will only be on for 5 min or so. But I suspect that I'm going to be wanting to drain the entire res and refill, so that could take 45-60 min. My intuition is telling me that having the pH badly out of whack is far more stressful than interrupting their sleep, so I'm sort of leaning in that direction. But I'd love some expert input here.
Help_Needed Reviewed by Help_Needed on . Fix pH or respect 12/12 lighting cycle? My new, expensive, electronic pH meter died last night. After 3 consecutive readings that indicated my reservoir pH was too high, it occurred to me that I might need to recalibrate. When I did, the meter reading started at 7.6 and then slowly climbed to 16 and then the meter quit working. Unfortunately, before I caught on to the fact that there might be a problem, I added a significant amount of pH Down to my res. I suspect that reservoir pH is now way too low - possibly as low as 3.5 - Rating: 5