Can't get PH up

[DavinD]

OK, I have read Randy's articles and am still having a PH problem.

I have a 20 gallon with a 5 gallon refugium and a 10 gallon sump about half full. My PH is consistenly around 7.6 to 7.7 (sometimes dips to 7.5). I've been dosing Kalk to no avail. I finally chalked it up to just bad substrate or something else.

Now, I have just filled my new 90 gallon with water and have only the arogonite in it, no live stock and no live rock yet. My PH is still only 7.7. Why would it be so low right off the bat? I use a PH probe on my AquaController and have calibrated it twice.

[Billybeau1]

Did you do the aeration test in the article ?

We need to see first if it is a CO2 issue.

[DavinD]

I guess I missed that part. I will try it tonight.

[bertoni]

How was the probe calibrated? With which pH buffers and which brand?

[DavinD]

I used 7.0 and 10.0 from pinpoint.

[bertoni]

Okay, that's a good choice for calibration. Let's see what the aeration test says.

[DavinD]

I just started the outside test. I assume I can bring the cup back in to measure PH as long as I do it quickly? I don't want to unplug my AquaController.

[bertoni]

Yes, that should be fine.

[DavinD]

OK, something is seriously wrong with my probe. After aerating outside, the PH read 6.63! I then put the probe back in the sump and it jumped to 12.3! I don't have any calibration fluid to re-calibrate.

I'll post something in a couple of days when I try to re-calibrate or replace the probe.

[bertoni]

I would check for electrical interference. If possible, the AquaController could be plugged into a receptable away from the tank. I don't know what else might cause those measurements, unless the probe is very dirty or shot.

[DavinD]

Well.....I just tested my water the old fashioned way with a Red Sea test kit that is about 2 years old. Low and Behold, It reads about 8.2, straight from the tank.