Hi guys, was wondering if you know of any sites that sells good pH probes (not dried out ones before they were even use) and ships internationally. The experience with those bought locally have been rather bad as non seem to hold the calibration well(reading drifts around). Tom, where did you get yours?

Regards
Peter Gwee

Cole Parmer has a good selection: http://www.coleparmer.com/

(They are available internationally: http://www.coleparmer.com/dealers/default.asp )

For example a nice double junction probe:
http://www.coleparmer.com/catalog/pr...sp?sku=5900170

A couple of related articles you might find useful:

Measuring pH with a Meter

A Comparison of pH Calibration Buffers

Rich

Rich, thanks for the site. Do you have personal experience in buying from them? Did the probe came in good condition (non-dried up probe head)?

Regards
Peter Gwee

I'm looking at the probe I pointed to in my reply as I write. I haven't put it in use yet and I've had it for a couple of months. The storage solution bottle at the end of the probe (and it is a small bottle, not just an end cap) is still full of solution.

I should be putting it into operation in a few weeks and I'll let you know how easy it is to calibrate.

What's the best way to clean these things anyway?

I check mine every month or so and notice a very thin circle of black crap between the sensor and the tube. This doesn't seem to be affect the sensor. The gap between the sensor and the tube is too small for a Qtip. So I'm not sure what to use.

Just installed that Cole-Palmer pH probe. Calibrated pretty easily and as a bonus seems to be affected less by a nearby powerhead than another type of probe I was using.

Thanks for the info Rich.

Regards
Peter Gwee

Does anyone know what type of PH monitors that this probe is compatable with? I have an American marine type with BNC. Will that work with pretty much any probe with a bnc connector?

Thanks!

The Hanna Checker 1 pocket sized pH meter is adequate for aquarium use and is reasonably priced $20-$30 on ebay. The probe lasts for about a year and can be replaced for about $18.

I work in a calibration laboratory and have access to good reference solutions. The meter worked well, up until the probe finally died (the point to where I could nolonger adjust the 2 point calibration to match the buffer solution values).

To be fair I did not use this probe continuously, only periodically to check my pH to make sure it had not changed drasticaly from where I thought it should be, and I calibrated it before every use. I also stored it dry with just the rubber cap over the sensor, and didn't use the recomended storage solution. I went several months of use before I had to make any adjustment after the first couple of calibrations. Durring this time it consistantly read correctly within 0.05 pH between 7.0 and 10.0 even though Hanna specs it at an accuracy of 0.2 pH. It has a resolution of 0.01 pH.

I trusted the reading on this meter more than any of the hobbiest liquid test kits.

My opinion is that even though it is not nearly as good as a good laboratory pH meter, it's great for home use, however I would suggest calibrating it at least once a month to maintain the accuracy I managed to.

Has anyone tried this one? http://www.automatedaquariums.com/h_1001.htm

I got T5's and they produce a lot of interference, so it might be a good idea to move the probe away from the lights.

And would it be ok to hook it up on my Milwaukee SMS controller?

Vidar