pH probe calibration

[simion3]

I tried calibrating my pH probe but it says it was unable to calibrate. What happened?

[bpd964]

Are you using old calibration solution?

[RobbyG]

Keep the calibration period low. If you take too long you will get that error.

Best way I have found is.

1) Clean probe, (Never use RO water) Dry properly by gently dabbing with paper towel

2) Have a cup of fresh water and a paper towel ready

3) put probe in 10.0 solution for 15 minutes.

4) After 15 minutes pass, Now Go into Calibration mode and let it sit on 10.0 calibration for 30 seconds then press OK. (You already had it in 10.0 for 15 min so it already has a stabilized reading.

5) Next set menu for the 7.0 or 4.0 fluid.

6 Quickly wash off probe in glass of water and dab dry with towel

7) Dunk probe in 7 or 4 fluid and wait 5 minutes for reading to settle then press OK.

8) Done

The 15 minute pre dunk in 10.0 cuts the total calibration time in half.

[gigiba]

don't use RO water? When you said fresh water, you mean tap water?

<a href=showthread.php?s=&postid=8508158#post8508158 target=_blank>Originally posted</a> by RobbyG
Keep the calibration period low. If you take too long you will get that error.

Best way I have found is.

1) Clean probe, (Never use RO water) Dry properly by gently dabbing with paper towel

2) Have a cup of fresh water and a paper towel ready

3) put probe in 10.0 solution for 15 minutes.

4) After 15 minutes pass, Now Go into Calibration mode and let it sit on 10.0 calibration for 30 seconds then press OK. (You already had it in 10.0 for 15 min so it already has a stabilized reading.

5) Next set menu for the 7.0 or 4.0 fluid.

6 Quickly wash off probe in glass of water and dab dry with towel

7) Dunk probe in 7 or 4 fluid and wait 5 minutes for reading to settle then press OK.

8) Done

The 15 minute pre dunk in 10.0 cuts the total calibration time in half.

[RobbyG]

Yes Tap water.

BTW if your doing a major cleaning of the probe, using probe cleaning chemicals, dont even attempt calibration right away. You need to put the probe back in the Tank for a day and let it settle down before calibrating. This is marked on the probe cleaning chemical bottles but is often ignored.

[gigiba]

Do you calibrate your Ph probe right out of box?

Thanks

[RobbyG]

Yes, Out of the box the AQ has know way of knowing the values till you do that first calibration.

[gigiba]

ahh.. I didn't do that.

ok, I bought ph10 and ph4 fluid from AO and it looks like the fluid came with couple small bags. Are these bags "one-time use only" for calibration?

Sorry for the dumb question, I have never done this before and still learning.

Thanks

[dbond]

You should save the fluids to reuse them for future calibrations
I recalibrate my probe every month or so and reuse the same fluid should be good for a while exactly how long Im not sure but I would think you should be able to get 1/2 dozens calibrations before changing.

[RonBuck]

No you should not reuse them. You can if you like but have a PH tester test the fluid to get the proper value. The PH fluid loses concentration after each use. Temperature effects the values as well.

[dbond]

<a href=showthread.php?s=&postid=8653537#post8653537 target=_blank>Originally posted</a> by RonBuck
No you should not reuse them. You can if you like but have a PH tester test the fluid to get the proper value. The PH fluid loses concentration after each use. Temperature effects the values as well.

Thanks Ron
I guess I have been doing it all wrong, I have reused the same calibration fluid 3 times now cleaning the probe each time did not realize it was only single use, although my probe seems to be giving me proper readings so far.
I should of asked you about this today when I was at the shop.

[RonBuck]

<a href=showthread.php?s=&postid=8653892#post8653892 target=_blank>Originally posted</a> by dbond
Thanks Ron
I guess I have been doing it all wrong, I have reused the same calibration fluid 3 times now cleaning the probe each time did not realize it was only single use, although my probe seems to be giving me proper readings so far.
I should of asked you about this today when I was at the shop.

It's not a huge deal. If you are confident enough that you are getting good readings. I personally don't trust the fluid is good over and over.