Ph Monitor vs. Ph Kit?

[GaryP]

OK, here is what an old lab rat that used a pH meter daily as one of his tools has to say about it.

1. The "special" storage solution is potassium chloride. This resores the potassium ions inside the probe.

2. I think that continuous use is a problem. The reason is that a film will develop over the electrode preventing it from operating properly. I suppose this can be overcome by VERY routine cleaning. I think that continuous use would eventually deplete the potassium ion in the electrode and thus shorten the life expectancy of the electrode.

3. We always calibrated our meters on a daily basis.

4. Electrodes should be cleaned with RO or distilled water after use, but never stored in RO or distilled water.

5. Small pocket sized pH meters (similar to TDS meters) are available. I have one. Another alternative are test strips, but I am not sure whether they are available in salt water pH ranges. The ones I used were 0-14, but I know theat more specific ranges are available. I will do some checking to see if a sea water range
(7.5 -9.0) test strip is availabe.

Gary

[GaryP]

Pocket pH Meters:

http://www.professionalequipment.com...qx/default.htm

http://www.sciencelab.com/page/S/CTGY/21771

http://www.hydroponics.net/c/64

[GaryP]

It looks like there is a test strip available from pH 6.5-10. Its accuracy is only about .2-.5 pH units though. It would tell you if there was a major problem, but not give you a specific pH value.

Gary

[Inno]

Thanks for the heads up Gary! Which Pocket tester do you own? I read through the links and am interested in this one: http://www.sciencelab.com/page/S/PROD/21771/50-HI98128

One thing none of the articles mention, unless I missed it, is how long before the electrodes (probe?) wear out...usually?

[GaryP]

I have an Orion. That's more of a professional model that I got through my old job. Its a bit pricey for a hobbyist. It depends on how often you use it and if you store it properly. I'd say they are good for 1-2 yrs. if used correctly.

Gary

[matt]

I have a dip probe called "the mini checker" that cost about $20. I don't store it in solution, just rinse it out after every use and put the cap back on. I do claibrate each time I use it, though. You can get calibration fluid pretty cheap ($10/pint) at analytical scientific.

[GaryP]

Matt,

Inside the cap should be a sponge that you can soak with storage solution. You can use pH 7 calibration standard as storage solution. The important thing is that you don't want it to dry out. RO water should never be used as storage solution.

Gary

[Inno]

Did some digging and found another handheld:

http://www.coleparmer.com/catalog/pr...p;lstBool=true

This one was recommended by Randy on RC.

Thanks for all the help Gary