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 - 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.

hey Help_Needed good to see you again

dont worry about interupting the light cycle, PH that low could be real detrimental to the plants in hydro.

when you get your new meter and calibrate it, get a chemy PHtest kit for a backup, anything that needs calibrating you cant rely upon totally

Thanks as always, Ganja.

Just got back from the hydro store with the new meter. As soon as the initial set up and calibration is done, I'll get things fixed.

I agree....fix the ph or you may not be worrying about the lighting at all. ;)

Thanks for the help, guys. The situation was worse than I thought - the pH was down to 2.4 :eek: And of course, Murphy's Law strikes and the roommate decided to stay home from work today, so I can just drain and refill.

So, I've added in enough pH Up to bring it to 5.4 and I'll try to get the res changed out tomorrow.

Hope you caught it in time.....keep us updated....good luck.

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Originally Posted by Weedhound

Hope you caught it in time.

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I think I did. As of this morning only a single leaf on a single plant (the biggest) showed any sign of problems. And, although I didn't spend a lot of time in there, the plants still looked ok, so they *should* be alright.

One thing I've learned the hard way about hydro is that nute problems tend to hit hard and very fast, especially compared to soil.

whew....:thumbsup:

Well, all's well that end's well. pH is back to a healthy 5.6. A few of the leaves are showing some spotting from the pH lockout, however there doesn't appear to be any root damage and aside from the damaged leaves the rest of the plants look healthy.

Thanks for the help guys.