Can't get predicable readings from PH probe

[Dolfan-Mike]

I've been chasing PH reading problems with my Apex Jr system for months and months. First off for years my system was rock solid with PH readings, then finally the PH probe failed and I replaced it with a PinPoint, this one worked well for about 6 months then started to give me erratic readings. I purchased a cheap no-name probe off Amazon and it actually worked for about 3 months then it was giving poor readings.

So today I did a few things

1. I did the probe reset with no probe and ran through calibration.
2. Then, I reran calibration using the PinPoint solutions that I had just opened. I let both the 7.0 and 10.0 tests settle for a long time, about 5-10 minutes for each.
3. Then I restarted, but left the probe in the 10.0 solution, and it read at 10.0 or 9.99
4. Then I moved the probe to the 7.0 solution, it read 7.1 pretty close
5. But then I returned it to the sump and after just a few minutes, it is now reading 5.4

I know my water parameters are in OK shape with a manual test showing probably about 8.0 so I know these reading like 5.4 or others like this are completely off.

What other ideas does anyone have? I can buy yet another probe, but I'm not convinced it will work.

 

[Troylee]

Try taking a cup of water from the tank and placing the probe in it.. you might have interference from something in the tank causing the whacky readings. Try moving it somewhere else in the sump also and keeping other wires away from it.

 

[Dolfan-Mike]

OK, well I rerouted all the lines and no real change. I tried with the lines changes to recalibrate two times, once on the PinPoint Probe and once on the Amazon probe. I gave both a ton of time to settle on a reading for 7 & 10 and when finished sitting in the 10 solution the probe read 10.

But then I put the probe into the tank and the reading falls quickly to about 6.2 as fast as the NASDAQ with tariff fears! :anguished-face:

So basically I just get crap readings in the sump but it seems to find the proper readings in the solution.

I may try now to put the probe back into the 7 or 10 and see how it reacts.

 

[Randy Holmes-Farley]

Can you see into the probe? Is there fluid inside?

 

[Dolfan-Mike]

Can you see into the probe? Is there fluid inside?

The PinPoint probe I can see that it has fluid inside as I see a small air bubble at the very top and moving it I see it move. The cheap Amazon probe is a solid black tube so can't see inside. I'm getting bad results from both probes

 

[Dolfan-Mike]

Today I did a firmware upgrade that was due for the Apex and then another VERY LONG calibration session but still way off.

Nothing I can do for now as I'm off on a vacation and will just have to hope the PH stays close.

 

[Randy Holmes-Farley]

OK, when you get back we can experiment some more. :)

 

[Dolfan-Mike]

Well pretty simple end to this story. I returned from vacation ordered another $19 probe from Amazon and as soon as I plugged it in without calibration, it was close. So I calibrated and now I have steady reasonable PH readings. Even if these only last a year I think I'll stick with these, maybe even keep a spare on hand.

 

[Randy Holmes-Farley]

Thanks for the update! :)