pH meter malfunction

[Halcyonmom]

Good afternoon! First time grower and up until now very few problems. However…today while preparing to water and fertilize I couldn’t seem to get my pH monitor to measure. It kept showing higher pH and I added a lot of PH Down and went ahead and watered my big girls that are budding beautifully and my clones which are coming along despite a rough start. Then I went looking for an answer to why the meter was reading high, calibrated and couldn’t get it to calibrate. In a panic, despite being quite Halcyon (calm,peaceful) most of the time, worried that my soil was way too acidic and that their Mom gave them Acid Rain unwittingly, I flushed everything twice with distilled water. I hope so much that they will be ok. Harvest is only a few weeks away. Here’s before pictures for reference. The strain is LSD 25 photo and they are being grown in soil under 400 watts. The grow tent contains 4 happy girls. I don’t have a grow journal.

 

[TorturedSoul]

I don't see mention of what brand/model of pH meter you are discussing, how recently you have replaced its probe, or whether you are storing it with the probe submerged in a KCl storage solution (/pH 4 01 calibration solution / whatever the manufacturer specifies). Have you recently installed a new light, fan, timer, or other electrical device? If so, a lot of them have crappy shielding (and most consumer grade meters have little to none), so a new device could cause wonky meter readings. Even, in theory, a new screw-in LED light bulb in the overhead fixture in the room that your grow tent is in.

 

[Halcyonmom]

I don't see mention of what brand/model of pH meter you are discussing, how recently you have replaced its probe, or whether you are storing it with the probe submerged in a KCl storage solution (/pH 4 01 calibration solution / whatever the manufacturer specifies). Have you recently installed a new light, fan, timer, or other electrical device? If so, a lot of them have crappy shielding (and most consumer grade meters have little to none), so a new device could cause wonky meter readings. Even, in theory, a new screw-in LED light bulb in the overhead fixture in the room that your grow tent is in.

Thank-you for your reply. No new light or fan. The pH meter is the cheap Vivosun that I got on Amazon with a TDS monitor for about $18. I have not been storing the probe in KCL solution and I suspect that is the problem. I've ordered another $45 meter with the correct solution. I'm hoping that this late in the game my big girls will be ok and that my clones don't croak. They got off to a bad start but have been looking better each day (sending out new growth) and I am hoping for the best. I guess they'll tell me soon enough.

 

[TorturedSoul]

The disposable (non-replaceable probe) type, with manual single-point calibration, comes with a little screwdriver to adjust a calibration screw?

I've had good luck with - and sometimes recommend - the Milwaukee Instruments pH56. Or, if someone is trying to save money (the pH56 is not super-cheap), the pH54, which only has ±.1 pH accuracy, but is accurate enough for the task. But most meters from most well-known brands - Milwaukee Instruments, Bluelab, Oakton, Hanna - would be fine. At one point, I was taking the crappy disposable digital Hanna meter home from the shop that was used (and abused) for checking the pH of people's engine coolant after we did flush and coolant filtration, lol, and the plants were okay.

As you discovered, it helps to have some idea of what to expect when you check pH, so that you'll have a clue when something has gone awry. An old-fashioned pH test kit (test strips) can also be helpful for this purpose, although I can state from personal experience that they aren't great if one has color perception issues. But, aside from that, a sudden drastic change in pH could be attributable to something other than a failed meter - such as a bloom of unwanted life in one's reservoir.

I'm happy to know that you've got a new pH tester coming, and hope it serves you well.

 

[Bigjake8]

Try a fresh battery had that problem once it would calibrate then reading would rise within 10 minutes if checked again about wrecked the whole crop funny part guess what it was yes lsd 25 haha its worth the battle
Looks good keep it up

 

[Icemud]

After having issues with multiple PH meters I decided to stop using them and went to the PH Drops.... I am so glad I did and never need to question the reading as the drops don't need calibration. Highly recommend keeping some drops on hand just in case you ever question the readings your pH meter is giving you.. the drops are awesome