pH Probes?

[pbnj]

Do all the pH probes out there require constant calibration?

[Randy Holmes-Farley]

Constant? No.

How frequently do you find you need to recalibrate?

Do you leave the probe in the tank water 24/7? In a lit area?

[pbnj]

I don't have one yet, just wanted to know more about them.

[Randy Holmes-Farley]

Ah, OK. The nature of the probe will matter some, but also a better probe may last longer and have less drift minute to minute. Aside from those issues, look for a double junction electrode, if possible. In selecting a meter, be sure it has at least 2 point calibration. A sealed electrode (not refillable) may be better for most reefers, but won't last as long since you cannnot replace the interior liquid when needed.

I discussed calibration in a thread yesterday. Here's what I wrote there:

The frequency depends on a lot of factors, but I agree that if anything looks unusual, check the calibration before doing anything else.

Also, try going longer and longer between calibrations. If it does not drift too much for your taste, then you can go longer. In some cases, you might do weekly, and in some it might be once per 6 months.

These may also be useful:

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

[SaltyNovice]

Tagging along - I'm interested in learning more about them also and how to use them with a controller. I'm looking for which controller that I want to buy now. Any information on these will be greatly appreciated (ph probes not controllers - I don't want to Hijack).

[Randy Holmes-Farley]

Do you want to "control" pH, or just monitor it?

[SaltyNovice]

For now, I guess monitor. I just do liquid tests right now and they seem always to be around 8.3. I'm not even sure ph is a problem for me. It's just more time consuming to test rather than just look at a screen. I'm not getting what I desire out of my tank right now. I probably have some water issues that I'm not smart enough to fix. I seem to have way too much nitrates and probably phosphate problems. Sorry, I really don't want to hijack this thread, but I'm working on water quality. Ive tried to read all your articles on water and chemistry Randy, but I guess I'm a dufus when it comes to chemistry smarts. I'm also in a rich man's hobby and probably shouldn't be.

[pbnj]

Great, thanks Randy!

[ALEX007]

Whats wrong with a refillable ph probe besides the price? What is the difference between lab grade and standard?

[Randy Holmes-Farley]

Nothing is "wrong" with them. I use them, and the best probes are often refillable. But reefers often have events where the whole probe gets submerged for substantial periods. Mine gets submerged any time there is a power failure. The concern is that despite the little mechanism to prevent liquid from getting out, these are not designed to go under water, so there may be some transfer of contents inside and out. That will mess with it.

What is the difference between lab grade and standard?

That's really just a marketing distinction which varies with every manufacturer. It means nothing in particular.

[Randy Holmes-Farley]

Ive tried to read all your articles on water and chemistry Randy, but I guess I'm a dufus when it comes to chemistry smarts.

Well, you can decide whether you'd rather be a dufus, and not know the chemistry, or be a geek like us and think about it all the time. There's no middle ground. :D

I think a pH meter is a good thing to get, but I wouldn't try to control pH, and so a controller may not be necessary. pH meters need not be especially expensive.

[KillerReef]

ok, my pH probe is in my sump with no ight. In your first post you asked about light 24/7. Am I getting a false reading by having it in the sump? It is right after my overflow in the sump if that matters. Thanks, Dave

[Randy Holmes-Farley]

No, I keep mine in my sump 24/7, but if it gets light on it, algae will grow on it and when lit, will give false readings, just like an ORP probe, due to local photosynthesis.

[KillerReef]

cool, thanks, had me worried for a sec... LOL

[vitimanc]

Mr. Holmes-Farley
What is the best way to clean a PH probe? Soft brush, maybe let the probe soak in a 4.0 ph solution and do a chemical cleaning? The probe I purchased (Bluelab) suggests a dishwashing detergent in a container giving it the swish technique to clean it and for those tough spots, put the brush to it, carefully, do you have any other tips/ideas on PH probe cleaning?

[Finsky]

I have a Pinpoint PH probe I keep in the tank 24/7 and I have just calibrated it for the second time to check a possible ph problem. My pinpoint was reading around 8.25 ph before I did my 10% water change this week with tap water which has zero phosphates and nitrates and a ph of 7.15 before the salt is added.

After my water change I had a reading of 7.84 and then I did a recalibration and got a 7.9 ph reading. I did a one dose of Seachem Reef buffer which is supposed to raise the ph by .1 and the ph came up to 8.12.

How could a 10% water change lower the ph so much?

I am really mystified?

[Randy Holmes-Farley]

What is the best way to clean a PH probe? Soft brush, maybe let the probe soak in a 4.0 ph solution and do a chemical cleaning?

I've never done or needed to do anything to mine beyond soaking them in acid (straight vinegar or diluted muriatic acid). Then recalibrate and it should be good to go. I don't like directly touching the glass bulb if you can avoid it as it is rather delicate.

[Randy Holmes-Farley]

How could a 10% water change lower the ph so much?

Time of day impacts pH, so that might be part of it.

What was the pH of that new water just before addition?

Did the probe get exposed during the water change? How long did you wait to see the new value?

[gonzapa]

Is it normal for the bulb to look "frosty" after a couple of months. I put in warm vinegar for 1 hour and still looks the same

[Randy Holmes-Farley]

Not sure, but if it calibrates and reads the calibration solutions corrctly, it is fine to use. :)