ISFET pH Meters

[pjf]

A couple of years ago, I purchased a non-glass ISFET pH meter from an American company similar to this Japanese one:
http://www.shindengen.co.jp/products_e/ph/index.html

They were under $100 at the time. I tested it with tap water, could not get a stable pH reading, and subsequently returned it. The company that I bought it from could not get it to fail.

If they have improved since, can someone recommend one? Thanks!

 

[pjf]

I recently noticed that Hach and Cole Palmer are now reselling pocket ISFET pH meters that are very similar to the meter that I used to own. My ISFET pH meter was unable to get a stable reading from tap water. Has the product quality improved in the last few years?

 

[Randy Holmes-Farley]

Try it in pH buffers, not tap water.