Very low PH

[toolfan]

hey guys & gals. I've got a bit of a problem with my 90g FOWLR. My ph was recently running a bit high (8.9ish)!! I tested with a salifert kit to confirm what my pinpoint monitor was reading and it came back lower (8.2). so I picked up some calibration fluid yesterday and dialed it in with 7.0 & 10.0 fluid. Now my ph is reading 7.02!! I also tested my DKH & Alk which came back at 12.2 & 4.34 respectively. I dont really trust manual tests & this monitor seems to be functioning properly. I dont get it. I dont supplement anything. I have done 15% water changes for the past 2 weeks as I always do. There is plently of circulation in the tank. 4 K3, a mechanical filter + my return so I dont think it's lack of oxygen.

I am leaning towards a bad monitor I suppose. It just doesnt make sense

Any thoughs?
Thanks

mark

[Randy Holmes-Farley]

I don't believe the pH 7.02 is correct. Maybe you calibrated it incorrectly, or there is interference at the tank with other electrical equipment.

If you put the meter into the pH 7 and 10 now, does it read both correctly?

[toolfan]

I just tested manually with a Tetra PH kit and it reads 8.0. I also just put the probe into some fresh 7 & 10 fluid. the monitor read 6.86 & 10.04.

[toolfan]

I just put the probe in the Skimmer section of my sump (also where water enters the sump) and the reading is 7.32

[boxfishpooalot]

Mines been super low too lately, dont know why. It could be I calibrated it wrong, or bacteria have covered the probe due to vodka dosing.

Are you dosing anything?

[toolfan]

No, I do not dose anything

[boxfishpooalot]

Honestly if your alkalinity is normal, ph is not ever going to be a concern. Unless your huffing and puffing into the air intake of a protein skimmer all day.... Or you never leave a 4x4 room for the whole day.

The only useful thing I believe a ph meter is good for is detecting Co2 drops due to bacterial growth(when dosing) and titration purposes for determining your alkalinity. :)

[tmz]

I think you ,may need to recalibrate. 6.84 on the 7 fluid seems too far off.
Try running your monitor no a battery instead of the ac adapter and change where you place the probe and the wire leading to it.

[bertoni]

I would recalibrate, and test a cup of water well away from the tank. My pH meter doesn't work well in the tank, due to electrical interference.

[HighlandReefer]

High CO2 in the room where your tank is? Try opening the door & windows in the room and put a fan to draw in fresh air. The pH should start rising within a couple of hours. :)

[Randy Holmes-Farley]

If the pH turns out to actually be low, this has more, but i suspect it is a measurement error:

Low pH: Causes and Cures
http://reefkeeping.com/issues/2004-09/rhf/index.htm

These have more on pH meters and calibration:

Measuring pH with a Meter
http://www.advancedaquarist.com/issues/feb2004/chem.htm

A Comparison of pH Calibration Buffers
http://reefkeeping.com/issues/2005-02/rhf/index.htm