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Hornet
03/03/2009, 07:34 PM
I'm trying to calibrate my Ph probe and I think it must be broke. I have some 7.0 & 10.0 solutions. I go to setup mode do the low end. Reading on the display does not seem to stay on the same number for more than about 45 seconds and always says settling. I hit select and do the high side, display constantly says settling on the 10.0 reading too. I hit select and unit says defective probe.

If my probe was good would I see the display change to something other than settling? I'm guessing my ph is busted but I want to verify before I shell out cash on a new one :(

graveyardworm
03/03/2009, 07:38 PM
Mine always says settling. I wait till the number hasnt changed for about a minute, or longer. If you're getting a message that states defective probe though. I would suspect a faulty probe. How long have you had the probe, has it ever been allowed to dry out, have you ever cleaned it?

Hornet
03/03/2009, 07:51 PM
The probe has never been used. I bough it NIB from somebody else but me being a noob I took the black cap off and spilled out some of the fluid in there. Did not realize till later that it was there for a reason. The probe then sat for a few months as I was moving rather slow on my build.

Oh well :(

BillyBee
03/03/2009, 08:42 PM
Make sure you have the temp probe in the same liquid as the pH probe. I was getting the same thing until I did that. The is some sort of relationship between the temp probe and the pH probe.

graveyardworm
03/03/2009, 08:44 PM
<a href=showthread.php?s=&postid=14529904#post14529904 target=_blank>Originally posted</a> by BillyBee
Make sure you have the temp probe in the same liquid as the pH probe. I was getting the same thing until I did that. The is some sort of relationship between the temp probe and the pH probe.

? That doesnt make any sense. For calibrating? Even for measuring the value of the water both probes should be able to be in completely different tanks and give accurate readings.

Hornet
03/03/2009, 09:05 PM
<a href=showthread.php?s=&postid=14529904#post14529904 target=_blank>Originally posted</a> by BillyBee
Make sure you have the temp probe in the same liquid as the pH probe. I was getting the same thing until I did that. The is some sort of relationship between the temp probe and the pH probe.

I just tried that but it did not work.

Mako
03/03/2009, 10:22 PM
<a href=showthread.php?s=&postid=14529928#post14529928 target=_blank>Originally posted</a> by graveyardworm
? That doesnt make any sense. For calibrating? Even for measuring the value of the water both probes should be able to be in completely different tanks and give accurate readings. Temp probe acts as a ground reference IIRC, and does have to be in the solution at the same time for proper calibration.

You can try soaking the probe for a few days in one of the cal solutions to see if you can get it to come back, but more than likely it's a gonner. Permanent damage occurs when left dry for extended periods of time.

graveyardworm
03/03/2009, 10:31 PM
I dont recall that in the pH probe calibrating instructions but would have to double check, its been a little while since I looked at them.

I have calibrated my pH probe numerous times without putting the temp probe in the solution and never had a problem.

Isnt the temp probe comletely sealed? If so how would it act as a ground?

Now I'm wondering, will have to do a search maybe the answer os there.

BillyBee
03/04/2009, 06:09 AM
Do a SEARCH. Curt has said the same thing.

pgordemer
03/04/2009, 07:21 AM
Placing the temp probe and ph probe together for PH calibration only applies to the AC Pro Series.

Hornet
03/04/2009, 07:34 AM
I just have the regular AC III. It did not make much sense to me but what do I know. I was the dummy that took the cap off and let the fluid out while I was still storing the probe, so I tried putting the temp probe in the solution too and it did not make a difference.

Kinda wierd, the reading I'm seeing on the display makes me think the probe is working. I'm going to compare the reading I'm getting on my probe with another source to see if it's correct. If it is I'll just move getting a new probe further down on my list of things I need to buy.

graveyardworm
03/04/2009, 08:43 AM
The only references I found for placing the temp probe and pH probe in the same fluid was when you were also doing a temp compensation.

Regardless of all that I believe the problem here is the probe was allowed to dry out for an extended period.

Hornet
03/04/2009, 09:09 AM
I'm now of the same opinion that the probe is bad. But I know I have another probe for measuring PH around the house somewhere. I want to try that out in both solutions and then in the sump. I'm just wondering if I'd get the same reading.

The ph probe for my aciii is reading about 7.9 in my sump now. I just want to know if I'd get the same reading on another probe that I verify is working properly. Either way I know I need a new probe. I'm just a bit curious of what the result will be