pH is at 9.4

[udsmkh]

I saw a dip in my Mg level back in December (1170 ppm) so I started adding Continuum Aquatics Reef-Basis Magnesium Dry Form. I have added a total of 100 grams over the last 30 days. I noticed my pH probe was climbing towards 9.4 but I thought it needed to be calibrated. Well I went to calibrate it and it was spot on. :shocked: I started to be concerned.

I checked all my parameters and they were: 79.3 F, 1.025 salinity, Mg 1245, Ca 443, Alk 7.7 (previously my Alk was 8.4 on New Year's Day). Last night I added 750 ml of Perrier to try to lower the pH but it is still about 9.2.

The tank is a year and a half old. 120 gallons with 20g sump that aerates very well and has a ASM G3 skimmer. Total water volume is 100 gallons. It is a mixed reef and has a moderate bioload of fish (6 fish, the biggest is 3 inches).

I don't understand why the pH is not dropping sufficiently or why it started climbing in the first place. What am I missing here?

 

[msderganc]

I'd say this has to be a bad probe - are your corals ok? I can't imagine anything living in 9.4 pH water.

 

[redfishbluefish]

Can't be 9.4! How old is the probe? Have you ever let the probe get totally submerged in water? Have you cleaned the probe....soak it in vinegar overnight? When you say you calibrated the probe, did you use both pH 7 and pH 10 buffers?

Again, a pH of 9.4 is impossible unless someone sabotaged your tank.

 

[udsmkh]

I have placed the probe in both buffer solutions and it reads 7.06 and 10.18. I am calibrating the probe now. I had given it a vinegar bath a few weeks ago.

 

[d5332]

at 9.4 some of your fish would have jumped out or died trying and your corals would probably be showing signs of death.

Is your tank looking normal or have weird things been happening in the past few weeks....

 

[udsmkh]

This is weird. I calibrated the probe and it measured both buffer solutions correctly. I filled a small glass jar and a small plastic bucket with tank water. The probe read 8.09 when placed in either but it would read 8.98 when in my sump. I then removed my grounding probe from my sump and now the pH is reading correctly (8.10). Anyone know why it would do that? I really don't like the idea of running with out the grounding probe.

 

[udsmkh]

All my fish and coral are doing fine except for my strawberry fields monti.

 

[redfishbluefish]

I would check to see if you have something with a voltage leak. If you have a VOM or mutimeter, it's easily tested. Set the meter to volts AC and put one probe in the tank and the other to a good ground. You can use the ground hole in a typical outlet.

 

[miamiangler]

Are you using a GFI outlet with the grounding probe ? If not the grounding probe will be useless

 

[udsmkh]

Yes, it is a GFCI. I will try to measure voltage later tonight. Thanks for the help everyone.

 

[Randy Holmes-Farley]

Electrical interference is a fairly common issue, and doesn't necessarily mean a problem with another device.

What brand meter?

 

[Randy Holmes-Farley]

It sounds like a ground loop issue. I can't link it at the moment, but it is a well known problem. Try googling pH and ground loop.

 

[udsmkh]

It is a Digital Aquatics probe.

I'll look that up. Thanks!

 

[Randy Holmes-Farley]

Hopefully you can find a solution.