PH has started to rise and continues to rise

[carleast]

My PH used to be between 8.10 and 8.2. Now I have added some chaetomorph to the refugium and added a few (5) fish to the main tank, my PH has started to climb. It is now in the 8.45 range. Could this be caused by the chaetomorpha processing the CO2 in the system? I have noticed that the chaetomorpha is starting to get bigger now.

I am going to try and prune some of the chaeto and see if that will lower the PH back to the 8.1 and 8.2 range.

[ReeferMac]

It could.... I'd suspect the added fish would work things in the opposite direction however? Over how long have you noticed the drift? Change _anything_ else? ph in a closed environment can be tricky, it could just be the probe aging/losing calibration if it was a slow and gradual change (that just happened to coincide w/ your other changes).

- Mac

[carleast]

it has happened in the last 3 days that the ph has been rising. before i put fish or chaeto into my system the ph remained low (ph < 8.15 to 7.90).

by the way. this tank has only been setup for about 4 weeks.

I will try and post the ph graph when i get home.

by the way. i am using a aquacontroller ii with the ph monitoring.

[ReeferMac]

Ahhh... give it time. Tank's too young to be sweating pH fluctuations like that.

- Mac

[carleast]

i was just worried that it keeps going up. I was going to setup my calcium reactor which uses co2, so that should lower my ph correct?

[carleast]

i was just worried that it keeps going up. I was going to setup my calcium reactor which uses co2, so that should lower my ph correct?

[carleast]

at what upper ph limit should i start to worry?

[richfavinger]

I just talked about this with one of the RC Staff.
I had LOADS of algae in the system, I had MAJOR pH swings, from 7.9 at night to 8.6 in day. :(

So I added herms' / snails, and trimmed out the algae, now the pH has stabilized, and is around 8.35 in day, and 8.00 at night. pH WILL swing 3 or so points, and I was told not to worry too much.

I was also told that Ca/CO2 reactor will not really solve the issue, (it's what I was thinking). Check your Mg level, as well as your Alk/dKH, and Calcium. I also moved the filter tubes to make more surface agitation; for more CO2 / O2 exchange.

Rich

[carleast]

i added the hermits, snails a couple days before i noticed the ph up swing.

ill try and trim some of the cheato from my fuge and see if that helps.

[carleast]

i also have my fuge setup on a reverse lighting scheme from the main tank. when i get home ill post some more specifics about the ph.

[carleast]

i figured it out. it was a grounding loop from my computer that is attached via the serial cable to my aquacontroller.

i performed a ph test with a manual kit and it came back normal ~8.0. the aquacontroller was saying that it was 9.4.

[richfavinger]

Ouch!!!
Yes probe's can be thrown by electrical interference. Don't loop the pH probe cable or AC (if your probe uses one) over any other cables. And if you run more then one probe (like ORP) put the probes about 6" apart in the water, and in good flow.

Also keep the tips clean, a small tooth brush works well, remember to power off the probe when cleaning, and try to keep the tip damp, or wet at all times. Also remember to calibrate monthly with pH 7.0 for main, and 10.0 for your slope. Replace your probe yearly.

Remember to read the directions on the pH calibration solution as well, they are temp. senctive, there pH at say 68F will not be the same as pH at 80F, so read the chart!

Rich :)

[ReeferMac]

Ditto what Rich said.... and keep an eye out for Randy's upcoming article on Calibration fluids (surprising results!) Glad the problem was resolved easily.

- Mac

[carleast]

thanks for your help.

i was freaking out that my ph kept going up/ orp going down. i spent alot of money on LR, etc. and didnt want to see it die.

The aquacontroller has a temperature compenstation for the ph calibration should i use that?

[Randy Holmes-Farley]

Could this be caused by the chaetomorpha processing the CO2 in the system?

Yes, high pH can be caused by CO2 consumption, but rarely will that alone lead to excessive pH. I'd not worry about high pH unless it rises above pH 8.5. However, I'm glad it wasn't 9.4 :D

As to the meter compensation, yes, you should use that, but it does not compensate for the pH change in buffers used for calibration. It adjusts for changes in the probe itself. Most buffers will say what temp they should be used at, and often show how the ph changes with temperature.

This article may help:

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

[carleast]

Thanks Randy,

Actually my PH monitor was showing 9.4 last night, then i unplugged my serial connection to my computer and the ph monitor immediately went down to 7.98. I ordered the ground interupting serial connection and that should rectify the misreporting ph probe.

[Randy Holmes-Farley]

You're welcome.

Here's a thread on the interference:

http://archive.reefcentral.com/forums/showthread.php?s=&threadid=344393