Why is my PH rising?

[The Grizz]

According to my Ph probe my tank is sitting @ 9.09.

[Lampshade]

When my Halides turned on my PH would always go up .2 or more after i moved my controller to the new location. Moved some cords around, and made it spike up .5 when the halides where on.

Make sure you're not running the wire near ANYTHING electrical. They gain 0.41mV per PH, so having electrical wires around them can easily change that. Just mentioning in case you've moved some wires around recently that could be causing it. It's most likely the increased O2, lots of people have summer/winter PH levels because of more windows being open.

[Gripenfelter]

Probe needed re-calibrating. Thanks everyone.

[Gripenfelter]

Still goes up. Not as much but still going up.

When I re-calibrated the probe it went to 8.13. Down from 8.37. All yesterday it was at 8.19. This morning when the lights came on it was 8.22.

I have my RO/DI unit set to run for 30 mins per day to top off the water.

Nitrates and Ammonia are 0.

PH test verified probe reading.

Sump gets lots of bubbles from overflow.

[Myka]

How old is the probe and what brand? Often times when probes start dying they start losing their calibration.

Fwiw, CO2 isn't the only cause on low pH. Decaying organic matter will lower the pH as well which is why many tanks that have high nitrate also have low pH.

Originally Posted by The Grizz

According to my Ph probe my tank is sitting @ 9.09.

I doubt that is accurate. Have you calibrated lately?

[Gripenfelter]

I verified the probe reading with an actual PH test and it's accurate. Seems to be stable though. Still sitting at 8.19 over night and 8.22 during the day so not bad.