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RE: How do you test a CO2 Probe

916 Views 3 Replies 4 Participants Last post by  inkslinger
RE: How do you test a CO2 Probe

I have been having trouble with my Pressurized CO2 system. I filled the 5lb tank several times and it has depleted quite fast.

When I first got the tank it lasted at least 6-9 months, maybe longer. Now I filled it and the Tank and the tank pressure looked good. The tank emptied with in about 3-4 weeks. Then I filled it again and checked for leaks, something I did the first time. NO leaks were found. Don't ask how I checked the tank for leaks unless you don't know how that is done. I use some Snoop. The tank again emptied fairly quick about 6 weeks this time.

I have noticed that the CO2 has been on longer than when the system was new, and the SMS 122 would show a higher pH than it is set for. I have it set at 6.8 but readings would be around 7.1 and takes forever to get to 6.8 if it does that at all. The reason I say that is that the tank it is hooked up to is not at my primary home and I do not moniter frequently. It may be on constantly. I just don't observe it but 2 times a week and most of the time the CO2 is on.

I have checked the calibration of the MA911B/2 CO2 probe and it seems to be ok when using 7.04 calibration fluid. But I still think that there might be an issue with the probe since when tested with the cal. fluid it seems to be ok but the CO2 seem to be on constantly and is drained from the tank in just a few weeks.

My question is how to test the probe with another method other than just calibration fluid. I have read somewhere that you can use Windex W/ ammonia to determine if the probe is working properly. You would dertemine that by reading the pH results on the moniter. Has anyone read or knows of a way to test the probes to see if they are working properly???

Once again, I have checked to see if I have any leaks and none have been found, but CO2 tank is being drained quite quickly and I suspect that the probe is no longer working properly but want to test before I spent the $30.00+ for a new probe.


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Re: How do you test a CO2 Probe

If I understand this right, the pH controller shows a higher than set point pH at all times, so the pH doesn't ever drop to the set point, as shown on the controller. Doesn't that mean that the probe is working fine? I'm not sure what else the problem could be, since you know you have no leaks.
Re: How do you test a CO2 Probe

the best way i have found to check them is with 2 diff P.H. solutions. 7 and 4. make sure it reads them both and see how long it takes to change from one to the other. if it takes a long time then the probe is bad. In my manual for my sms122 it says to calibrate with both 7.04 and 4ph solutions yet they only send the 7.04. Also the sms122 is supposed to shut off if it thinks its running to long with no change and then try again later (don't know times) to prevent itself from dosing to much.

I Also use a drop checker because i dont trust my ph controller. because their are alot of things that can trick its readings. another trick i do is have my bubble counter set at a normal rate i.e. 2bps so even if it does somehow get stuck by either a solenoid failure or a controller failure it still wont raise the Co2 in the aquarium to dangerous high or low levels.

just my 2 cents.

good luck
Re: How do you test a CO2 Probe

I also have the the SMS PH Controller and i just redid my 110g tank it was down for sense Thanksgiving of last year, so when i put everything back together in March i notice i had to replace a lot of thinks in my system , from gaskets dry rot to light been to old , when i filled my tank an tested my Controller the first think i replace was my probe. i knew it had been over a year , i set my controller to 6.7 but notice the 2nd day that the PH was still at 7.1, i new something was wrong, i check everything before then i notice i did not replace an O Ring on the Bubble counter an the co2 was leaking out,
i bypass it an went striae into my co2 reactor an my ph drop to 6.7 , until i get around in getting another bubble counter it will stay that way.
use soapy water to check for and leaks on your co2 system. i'm planting on getting a ph drop checker for back up also in due time. an when you calibrate for your low's 4.0 you calibration slope adjustment screw is in the back of your controller not the front, and i think Milwaukee inc. says for freshwater you really don't need to check your low 4.0 only the 7.0 would be ok but i too like to check both
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