Question about new pH module and calibration

glb · May 23, 2018

I just hooked up my new ph module and wonder if I calibrated the probe correctly. The apex display gives the values of 7 and 10 ph for calibrating. Does it matter that my solutions say 7.01 and 10.01? Also, does the temp of the calibration solution matter that much? The temp on mine was probably 74-75. It says on the packet that the std is 78 degrees. I’m wondering because the pH the apex is showing seems low. It’s 7.8 while my old standalone ph monitor reads 8.3. An API ph test read about 8.0. Should I calibrate it again? Any help is appreciated!!

DLHDesign · May 24, 2018

glb said:
Does it matter that my solutions say 7.01 and 10.01?

The difference between 7.01 and 7.00 is so slight, it shouldn't effect things. You would get more of a variation from temp differences.

glb said:
Also, does the temp of the calibration solution matter that much?

Yes; you should float them in the tank for a few minutes (I do 10min) before calibration. I keep them in the water during calibration as well (using a small "chip clip" to keep them in place.
Note that (assuming you have a properly calibrated temp probe on your Apex) you'll want to enable temperature correction if you have not already.

Check for any kind of power cables or powered equipment on or around the probe or the probe's wire. These probes are pretty sensitive to electronic interference and a power cable running parallel to the probe cable can throw off the reading in frustrating ways.

glb · May 24, 2018

Thanks everyone. The pH seems really low. I’ll move the probe away from power cords and see if that helps. I can also plug the temp probe into the ph module right?

glb · May 24, 2018

DLHDesign said:
The difference between 7.01 and 7.00 is so slight, it shouldn't effect things. You would get more of a variation from temp differences.

Yes; you should float them in the tank for a few minutes (I do 10min) before calibration. I keep them in the water during calibration as well (using a small "chip clip" to keep them in place.
Note that (assuming you have a properly calibrated temp probe on your Apex) you'll want to enable temperature correction if you have not already.

Check for any kind of power cables or powered equipment on or around the probe or the probe's wire. These probes are pretty sensitive to electronic interference and a power cable running parallel to the probe cable can throw off the reading in frustrating ways.

Ps-my tank temp runs at about 75. Is that ok for calibration??

manilaboy1vic · May 24, 2018

oh wow.. i forgot to put my packets in the water the last time i calibrated.. oops.. guess ill be recalibrating tonite.. however, when i calibrated and updated the apex.. i put the probe back in the packets and it read the correct value.

glb · May 24, 2018

Well I moved the pH probe away from the other wires and it still reads about 7.9. I thought it was running at 8.1-8.3 but maybe not.

glb · May 26, 2018

Calibration madness. I bought new calibration fluid, floated it in the tank for about 20 minutes, then recalibrated. My ph is reading 7.73, which I don’t think can be right. The alk is usually between 9.7-10.2. I am very frustrated! I’m using a BRS probe with the apex ph module. Ack!

n2585722 · May 26, 2018

7.8 would not be uncommon in a closed up house. Higher CO2 levels will lower your pH. When my 5 grandkids stay over for the night my pH drops like a rock. I can tell when they come and go from the house during the day by looking at the graph. It will also change during the day normally.

glb · May 26, 2018

n2585722 said:
7.8 would not be uncommon in a closed up house. Higher CO2 levels will lower your pH. When my 5 grandkids stay over for the night my pH drops like a rock. I can tell when they come and go from the house during the day by looking at the graph. It will also change during the day normally.

You’re right. I had this problem with my nano. I guess the ph monitor I had was really off. It read 8.1-8.3 since the tank startup. I have an API test that reads 8.0. I know they’re not the best but I keep it as a backup. If this is the true ph, I worry about eventually keeping corals. I’m bummed because I thought the skimmer would help with aeration. I’m really bummed.

n2585722 · May 26, 2018

glb said:
You’re right. I had this problem with my nano. I guess the ph monitor I had was really off. It read 8.1-8.3 since the tank startup. I have an API test that reads 8.0. I know they’re not the best but I keep it as a backup. If this is the true ph, I worry about eventually keeping corals. I’m bummed because I thought the skimmer would help with aeration. I’m really bummed.

That pH level in itself should not prevent you from keeping coral. I am not sure how long you have had the probe give it a few days in the tank before calibrating it again.

glb · May 26, 2018

n2585722 said:
That pH level in itself should not prevent you from keeping coral. I am not sure how long you have had the probe give it a few days in the tank before calibrating it again.

Thanks. The probe is brand new. I put it in the tank a few days ago.