Bad pH probe or my water parameter is this bad?

disaster999

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I have a pH monitor on my tank for a few months, calibrated it per instructions and the numbers it detected looked "reasonable" to me and I had no reason to doubt it...until one day. It always read 8.1-8.4 on my tank until one day the reading just plummeted from 8.4 to 7.4 instantly and Ive been struggling to bring it back up to 8.4 since. I tried measuring various other things to make sure my prob is reading "correctly". Im dosing kalk so I dunked the probe in kalk water and it reads 12+ pH. Dunked it in citric acid solution and it reads around 4ish pH. My tank still reads 7.8-8pH at best.

This morning I woke up to my tank having only 6.6pH. I moved the probe else where in my sump, fully submerged the prob so its picking up the reading from the bottom of my sump and its reading 2.13ph???????? I lifted the probe back up near the surface and its reading 6.8ph. Theres no way in a sump with fast moving flowing through it that the bottom has a pH reading of 2. This leads me to think my pH probe is bad? Ill try and calibrate the probe again tonight to see if this makes any difference, but most likely I have to get a different unit.
 

gbroadbridge

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I have a pH monitor on my tank for a few months, calibrated it per instructions and the numbers it detected looked "reasonable" to me and I had no reason to doubt it...until one day. It always read 8.1-8.4 on my tank until one day the reading just plummeted from 8.4 to 7.4 instantly and Ive been struggling to bring it back up to 8.4 since. I tried measuring various other things to make sure my prob is reading "correctly". Im dosing kalk so I dunked the probe in kalk water and it reads 12+ pH. Dunked it in citric acid solution and it reads around 4ish pH. My tank still reads 7.8-8pH at best.

This morning I woke up to my tank having only 6.6pH. I moved the probe else where in my sump, fully submerged the prob so its picking up the reading from the bottom of my sump and its reading 2.13ph???????? I lifted the probe back up near the surface and its reading 6.8ph. Theres no way in a sump with fast moving flowing through it that the bottom has a pH reading of 2. This leads me to think my pH probe is bad? Ill try and calibrate the probe again tonight to see if this makes any difference, but most likely I have to get a different unit.
I'd suggest soaking the probe for an hour in a ph probe cleaning solution and then to soak overnight in a ph 4 or 7 calibration solution. Tomorrow try to recalibrate using ph 7 and ph 10 calibration solutions.

If after calibration it reads both the calibrations solutions correctly try measuring the tank again.
 
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disaster999

disaster999

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I'd suggest soaking the probe for an hour in a ph probe cleaning solution and then to soak overnight in a ph 4 or 7 calibration solution. Tomorrow try to recalibrate using ph 7 and ph 10 calibration solutions.

If after calibration it reads both the calibrations solutions correctly try measuring the tank again.
Thanks, Ill give that a try. I dont have any cleaning solution tho. Google tells me warm soupy water would work as well?
 

Peair

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I have a pH monitor on my tank for a few months, calibrated it per instructions and the numbers it detected looked "reasonable" to me and I had no reason to doubt it...until one day. It always read 8.1-8.4 on my tank until one day the reading just plummeted from 8.4 to 7.4 instantly and Ive been struggling to bring it back up to 8.4 since. I tried measuring various other things to make sure my prob is reading "correctly". Im dosing kalk so I dunked the probe in kalk water and it reads 12+ pH. Dunked it in citric acid solution and it reads around 4ish pH. My tank still reads 7.8-8pH at best.

This morning I woke up to my tank having only 6.6pH. I moved the probe else where in my sump, fully submerged the prob so its picking up the reading from the bottom of my sump and its reading 2.13ph???????? I lifted the probe back up near the surface and its reading 6.8ph. Theres no way in a sump with fast moving flowing through it that the bottom has a pH reading of 2. This leads me to think my pH probe is bad? Ill try and calibrate the probe again tonight to see if this makes any difference, but most likely I have to get a different unit.
Also open up the windows for fresh air, that will help your PH, this time a year when the weather changes seems to always have an effect on PH.
 

thedon986

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Sounds like it might be time for a new probe. You need to clean and calibrate and if it’s still in the 6s then it’s shot. I don’t believe 6s is really possible without major die off or crashing of everything.
 
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disaster999

disaster999

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Also open up the windows for fresh air, that will help your PH, this time a year when the weather changes seems to always have an effect on PH.
I actually have the sliding door to the backyard opened most of the time now so it should get plenty of fresh air.
 

gbroadbridge

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Thanks, Ill give that a try. I dont have any cleaning solution tho. Google tells me warm soupy water would work as well?
Nope, you need a cleaning solution.

pH probes should be cleaned regularly if they're submerged 24/7, so a bottle purchase is worthwhile if you want reliable readings.
 
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disaster999

disaster999

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Sounds like it might be time for a new probe. You need to clean and calibrate and if it’s still in the 6s then it’s shot. I don’t believe 6s is really possible without major die off or crashing of everything.

Nope, you need a cleaning solution.

pH probes should be cleaned regularly if they're submerged 24/7, so a bottle purchase is worthwhile if you want reliable readings.
Got it, Ill look for some cleaning solution soon.

In the mean time I gave the tip of the probe a scrub with a soft brush and some mild soap, rinsed it well, and calibrated it again. seem to be reading "normal now"
 

Sisterlimonpot

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None.of that replaces the need to recalibrate it.

if you want to rule out inaccuracy, you have to put the probe in a known pH solution. 7 and 10 buffers are what's common for most hobbyists.

You'll want to calibrate often to ensure accuracy. Because I heavily rely on pH, I calibrate every 30 days and have a new probe at the ready when the current one starts to fail.
 

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