lanman April 13, 2008 Share April 13, 2008 I am setting up my CA reactor, so I broke out the 2nd pH probe. While trying to turn it on - I accidentally un-calibrated the first pH probe. Couldn't find any 7.0 solution - so I calibrated both in 4.0 and 10.0. The original one reads 7.68 in my tank water after calibration. It should read about 8.2. The second one reads around 9.5 in the same tank water. Is that as close as I can get using 4.0 and 10.0?? Or is something going on I'm not aware of?? I did the calibration twice - and got the same results both times. Thanks, bob Link to comment Share on other sites More sharing options...
dtfleming April 13, 2008 Share April 13, 2008 did you clean them with distilled water before and after cal. I would get some 7ph and try it again. Link to comment Share on other sites More sharing options...
lanman April 13, 2008 Author Share April 13, 2008 did you clean them with distilled water before and after cal. I would get some 7ph and try it again. I just found some 7 in my original Pinpoint meter box!! Yay!! I'll try again after a while - I'm out of time right now. I cleaned them in RO/DI water - not distilled... Instructions just say 'fresh water'. bob Link to comment Share on other sites More sharing options...
Grav April 15, 2008 Share April 15, 2008 Bob, Glad you found some 7.0 FWIW, there is no point in doing both 4.0 and 10.0 with, or without, 7.0. simply put: you are adjusting the same thing (slope from the center point of 7.0) Phil Link to comment Share on other sites More sharing options...
lanman April 15, 2008 Author Share April 15, 2008 Bob, Glad you found some 7.0 FWIW, there is no point in doing both 4.0 and 10.0 with, or without, 7.0. simply put: you are adjusting the same thing (slope from the center point of 7.0) Phil The 7.0 that I found was a different brand than the 10.0 ... and the probes calibrated perfectly well - but OFF! After settling overnight, they both read 7.50 - but the water they were in is actually closer to 8.0 in the mornings. They rose together - always within .02 of each other - about the right amount; but still not 'right'. I have ordered some calibration fluids. bob Link to comment Share on other sites More sharing options...
YBeNormal April 15, 2008 Share April 15, 2008 Bob, I have some calibration fluid you can borrow while you are waiting on your order to arrive. I'm working from home tomorrow so you can pick it up whenever you have time. Link to comment Share on other sites More sharing options...
lanman April 15, 2008 Author Share April 15, 2008 Bob, I have some calibration fluid you can borrow while you are waiting on your order to arrive. I'm working from home tomorrow so you can pick it up whenever you have time. I got some Tunze calibration fluid - 7.0 and 9.0. I just did my first try with it, and they are closer - but this time they aren't matching very well. Will try again, with a looooonger settling period. I ordered Pinpoint 7.0 and 10.0; and yesterday bought a kit to measure pH chemically that I hope is more accurate than previous ones. This is turning into an interesting endeavor for someone that has always believed his pH probe. bob Link to comment Share on other sites More sharing options...
flowerseller April 15, 2008 Share April 15, 2008 Is this on an ACIII? Make sure temp comp is activated. Don't be suprised to find your probe is actually accurate as many people are experienceing lower than expected pH Link to comment Share on other sites More sharing options...
lanman April 15, 2008 Author Share April 15, 2008 (edited) Is this on an ACIII? Make sure temp comp is activated. Don't be suprised to find your probe is actually accurate as many people are experienceing lower than expected pH Hmmm... how do I activate temperature compensation?? NEVER MIND - I found it... (Edit) I think one of the probes might actually be bad... it calibrates funny - and gives wild readings sometimes. The pH test kit says my pH is 8.2 (closest it can read). The last time I calibrated, the good probe now says 8.05; which isn't far off from what I guessed it would be. The 2nd probe says something like 4.79; obviously out of range wrong. The 2nd one is brand new, by the way... bob Is this on an ACIII? Make sure temp comp is activated. Don't be suprised to find your probe is actually accurate as many people are experienceing lower than expected pH Now that I have temp comp activated... should I re-calibrate? bob Edited April 15, 2008 by lanman Link to comment Share on other sites More sharing options...
YBeNormal April 16, 2008 Share April 16, 2008 Have you tried swapping the probes around to make sure it is the probe and not the controller that is defective? Link to comment Share on other sites More sharing options...
lanman April 16, 2008 Author Share April 16, 2008 Have you tried swapping the probes around to make sure it is the probe and not the controller that is defective? I have not... guess I'll try that next! I re-calibrated the ph2 probe twice last night, and never even got close. bob Link to comment Share on other sites More sharing options...
lanman April 20, 2008 Author Share April 20, 2008 I picked up a new pH probe at BRK - and it calibrated and works just fine. No idea what might be wrong with the original one. Maybe I'll send it back to Neptune and see if they can figure it out. bob Link to comment Share on other sites More sharing options...
flowerseller April 20, 2008 Share April 20, 2008 I picked up a new pH probe at BRK - and it calibrated and works just fine. No idea what might be wrong with the original one. Maybe I'll send it back to Neptune and see if they can figure it out. bob Glad to hear Bob, How old was the probe in the first place? Did you say you calibrated it and then when you finished it it read 7 in the 7 solution? What is the pH now that you got a new probe/calibrated? Link to comment Share on other sites More sharing options...
lanman April 20, 2008 Author Share April 20, 2008 Glad to hear Bob, How old was the probe in the first place? Did you say you calibrated it and then when you finished it it read 7 in the 7 solution? What is the pH now that you got a new probe/calibrated? The probe is brand new - I have owned it since the group buy, but only just now setting up my CA reactor - so I pulled it out of the box and hooked it up. The very first time I calibrated it, it seemed to be working, although it took over an hour for it to settle down to match the other probe in the same tank water. After I got some more appropriate calibration fluid, I recalibrated both, and since then, that probe never even got close to accurate. The pH on the brand new probe is now 7.02... it is in my CA reactor - has dropped steadily overnight from a start of 7.82. How long would it normally take for a CA reactor to get down to pH of 6.8? I'm only bubbling about 15-20 bubbles/minute - do I need to crank it up a bit? When I calibrated it yesterday, just before lights on, the original read 7.81 and the new one read 7.82. I figured that was close enough! pH in the tank is currently 7.91; lights should come on in about 5 hours. I don't want to scare anyone... but I'm finally setting up my AC3 programming. First thing connected - CO2! bob Link to comment Share on other sites More sharing options...
Highland Reefer April 20, 2008 Share April 20, 2008 Link to comment Share on other sites More sharing options...
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