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ph Calibration
Posted: Sat Jan 21, 2012 3:16 pm
by agentgreen
Can someone help me out with this?
I pulled the PH probe out of the sump, and cleaned it off. I then entered the PH Calibration mode, opened up the 7.0 calibration fluid packet, and placed the probe in it. My PH 7.0 reading in the menu at start is 561. I then set a timer for 20 minutes. After the timer is up, the 7.0 reading is still 561.
I clean the probe off with water and dry it, and place it in a packet of 10.0 calibration fluid. ph 10.0 reading at start is 581. Same routine as above, 20 minutes later, it's still at 581.
Is this the proper way to do this? Are my readings right? I've seen on the forums my ph 10.0 readings should be more around the 800's.
Any assistance would help here!
Thanks!
Re: ph Calibration
Posted: Sat Jan 21, 2012 4:16 pm
by rimai
Yes, should go up to 800s.
Is it the first calibration or you've done it before?
Re: ph Calibration
Posted: Sat Jan 21, 2012 4:26 pm
by agentgreen
rimai wrote:Yes, should go up to 800s.
Is it the first calibration or you've done it before?
I've tried this a few times, all with the same results.
Re: ph Calibration
Posted: Sat Jan 21, 2012 6:02 pm
by rimai
I meant if you used the probe before and are calibrating it again or this is the first time you are trying to use the probe ever.
Re: ph Calibration
Posted: Sat Jan 21, 2012 6:27 pm
by agentgreen
rimai wrote:I meant if you used the probe before and are calibrating it again or this is the first time you are trying to use the probe ever.
Oh, sorry. Yea the probe has been in use before. Before my old tank cracked, I had it in the sump all the time, and tried to calibrate it multiple times. Then the tank broke, the probe was dry for about 3 months, and now has been back in the water for about a week. I tried to calibrate it again today.
Re: ph Calibration
Posted: Sat Jan 21, 2012 6:42 pm
by rimai
Sorry for your tank

But, pH probes can't really be left dry, but try this...
It should work. Place in vinegar for about 3 or 4 days and then let it soak in your sump for another 3 or 4 days. That should make the probe work again.
Re: ph Calibration
Posted: Sun Jan 22, 2012 8:13 pm
by rufessor
That may rescue it.... a pH probe has a porous opening between the probe internals (solutions, electrodes etc) and the external solution, which is how it can figure our what the pH of the solution its sitting in actually is. If you dry it out that opening tends to get clogged by precipitation of salts/organics (proteins etc) into/onto the holes which clog it and can cause exactly the issue your describing (more or less)... if the vinegar does not work there are other solutions more specialized to lab work that might save it... but honestly, for reliability I would simply order another if the vinegar does not work. They are not super expensive (I am actually surprised how cheap they are). If you work in a research lab you will be used to paying 10x the cost for a pH probe..... so I kinda consider these to be more or less a disposable item if they act up. Storing it dry for three months is bad mojo. Unsure if these are refillable... but you may even have managed to evaporate enough of the internal solution to cause issues... so if its at all odd just get a new one if you really care about it being right.
Re: ph Calibration
Posted: Mon Jan 23, 2012 7:55 am
by agentgreen
Cool, I will soak it in white vinegar for a couple of days. I'll let you know the results!
Re: ph Calibration
Posted: Wed Feb 01, 2012 8:26 pm
by rossbryant1956
I asked the other day if there was a post anywhere that detailed the ph calibration process. Can anyone help? Thx
Re: ph Calibration
Posted: Wed Feb 01, 2012 8:52 pm
by binder
rossbryant1956 wrote:I asked the other day if there was a post anywhere that detailed the ph calibration process. Can anyone help? Thx
http://forum.reefangel.com/viewtopic.ph ... tion#p5303
Re: ph Calibration
Posted: Wed Feb 01, 2012 8:55 pm
by rossbryant1956
thx very much!! Can you help with my client uninstall problem? ;>
Re: ph Calibration
Posted: Sat Feb 04, 2012 6:33 am
by ruckusman
WHere can I get calibration fluid. Was it supposed to be in the box?
Re: ph Calibration
Posted: Sat Feb 04, 2012 6:34 am
by ruckusman
Are there regular liquids we can use that we know have a ph of 7 and 10?
Re: ph Calibration
Posted: Sat Feb 04, 2012 7:07 am
by agentgreen
ruckusman wrote:Are there regular liquids we can use that we know have a ph of 7 and 10?
Amazon.com has them. I just bought these the other day.
http://www.amazon.com/Atlas-Scientific- ... 407&sr=8-8
Re: ph Calibration
Posted: Tue Feb 07, 2012 6:40 pm
by tkeracer619
Your lfs will have them if they are any good.
Might as well trash the probe IME. It might not last that long if it comes back. I wouldn't rely on it.
RA has a great price on good probes.
I wish probes came with calibration fluid and that RC cars came with batteries.

Re: ph Calibration
Posted: Tue Feb 07, 2012 6:45 pm
by wolfador
ruckusman wrote:Are there regular liquids we can use that we know have a ph of 7 and 10?
I bought them on ebay. I think they were about a dollar each including shipping.