New Apex ph probe issue

[bubbaque]

I purchased the new Apex a couple of weeks ago but have had none stop issues with the probe keeping calibration. I have calibrated the probe probably 6 times now all with new fluid each time. So today, I try and recalibrate the probe with TWO calibration packages of 7.01 and Two 10.01 to try and get a more precise calibration. I am just using one of each of the calibration fluids just to rinse the fluid off before I stick it in the new package.

I am calibrating the probe and I can get the probe to read 7.08 in the 7 package and 10 in the 10 calibration fluid, close enough for me. The issue is when I stick the probe back in the tank it gives me a reading and then I watch the ph number start to drop kind of rapidly. So I take the probe back out of the tank, rinse it in a 7 calibration fluid package and the number is no longer reading in the 7's, I get reading from 6.6 -6.8. The probe isn't holding calibration. What could be this issue?

 

[jwshiver]

I have never had an issue with my pH probe. Even when I clean it with vinegar it bounces right back. I'd say it is a bad probe. I would say as an aside that the ORP probe can take several days to settle. Good luck.

 

[jwshiver]

Sorry, I just had a thought (very dangerous). Make sure the wire to the pH probe is not around other wires such as your lights. You might be getting interference. You can buy shielding to wrap around the wire if that is the issue. This is what I used. I think the temp probe is more prone to interference. https://www.amazon.com/gp/product/B01BIBQ940/ref=oh_aui_detailpage_o05_s01?ie=UTF8&psc=1

 

[hybridazn]

Yes as stated above make sure the pH probe wire isn't around other high draw cords that could be causing interference. Also make sure the probe end is free of any debris and after you submerge the probe shake it around to make sure there aren't any air bubbles trapped. Also do this a bit when calibrating in the packets as well.