Anyway to calibrate PH w/o calibration solution?

dannieboiz · 04/25/2006, 05:02 PM

Is there any alternative to checking/calibrating your PH probe without having the actually calibration solution?

BLockamon · 04/25/2006, 05:12 PM

Doing an exact calibration w/o standards would be tough. Pure DI water should be about pH 7, but if you let it sit in the open air, the pH can drop as low as ~5.8 due to CO2 dissolving in it. Also, the DI water would have a conductivity so low, I'd worry about the usefulness of the probe.

If you're looking for a quick check, mix up some new salt water, aerate it, and check the pH. It should be about 8.2.

dannieboiz · 04/25/2006, 05:14 PM

I'm not in a life and death situation, just wondering if there are other ways around it.

the PH in my tank constantly reads 8.4 regardless of what my calcium reactor reads. :?

loudell · 04/25/2006, 06:08 PM

The short answer is that you can't check the meter without accurate calibration fluids. You can disolve some borax in deionized water and the resulting pH should be about 9.18 But if the 9.18 number is different you will need 2 calibration fluids to do the adjustment.

Nathan · 04/25/2006, 06:13 PM

DI water has a null pH.

extinguishfire · 04/27/2006, 04:05 PM

Once you open the ph fluid for calibration is it done with or can it be saved for future calibrating?

Nathan · 04/27/2006, 10:17 PM

If it is a small packet, then throw it away. If it is a jar, or larger container then keep it.

-Nathan

loudell · 04/28/2006, 07:03 AM

Actually if the calibration fluid is in a small packet it is most likely starting out as more accurate and potentially better suited for limited reuse. #10 fluid is relatively less stable than 4 or 7 fluid. The biggest issues for reusing the fluids will be the users technique in NOT contaminating the fluids, the storage in a clean glass container and the begining accuracy to be as high as possible. Having said all that I would not reuse calibration fluid for more and 5-6 weeks...

04/27/2006, 04:05 PM	#6
extinguishfire Registered Member Join Date: Apr 2004 Location: Dallas-Fort Worth Posts: 286	Once you open the ph fluid for calibration is it done with or can it be saved for future calibrating? __________________ 90 gallon bowfront for a year then upgraded to a 140 gallon in April 2005. Then in October 2007 started a 295 gallon in-wall build.

04/25/2006, 05:02 PM	#1
dannieboiz Registered Member Join Date: Mar 2005 Location: NorCal Posts: 2,514	Anyway to calibrate PH w/o calibration solution? Is there any alternative to checking/calibrating your PH probe without having the actually calibration solution?

04/25/2006, 05:12 PM	#2
BLockamon Registered Member Join Date: May 2005 Posts: 1,104	Doing an exact calibration w/o standards would be tough. Pure DI water should be about pH 7, but if you let it sit in the open air, the pH can drop as low as ~5.8 due to CO2 dissolving in it. Also, the DI water would have a conductivity so low, I'd worry about the usefulness of the probe. If you're looking for a quick check, mix up some new salt water, aerate it, and check the pH. It should be about 8.2.

04/25/2006, 05:14 PM	#3
dannieboiz Registered Member Join Date: Mar 2005 Location: NorCal Posts: 2,514	I'm not in a life and death situation, just wondering if there are other ways around it. the PH in my tank constantly reads 8.4 regardless of what my calcium reactor reads. :?

04/25/2006, 06:08 PM	#4
loudell Registered Member Join Date: May 2003 Posts: 367	The short answer is that you can't check the meter without accurate calibration fluids. You can disolve some borax in deionized water and the resulting pH should be about 9.18 But if the 9.18 number is different you will need 2 calibration fluids to do the adjustment.

04/25/2006, 06:13 PM	#5
Nathan Premium Member Join Date: Mar 2000 Location: Newtown, Pa., USA Posts: 1,454	DI water has a null pH.

04/27/2006, 10:17 PM	#7
Nathan Premium Member Join Date: Mar 2000 Location: Newtown, Pa., USA Posts: 1,454	If it is a small packet, then throw it away. If it is a jar, or larger container then keep it. -Nathan

04/28/2006, 07:03 AM	#8
loudell Registered Member Join Date: May 2003 Posts: 367	Actually if the calibration fluid is in a small packet it is most likely starting out as more accurate and potentially better suited for limited reuse. #10 fluid is relatively less stable than 4 or 7 fluid. The biggest issues for reusing the fluids will be the users technique in NOT contaminating the fluids, the storage in a clean glass container and the begining accuracy to be as high as possible. Having said all that I would not reuse calibration fluid for more and 5-6 weeks...