No personal expierence with. I was going to buy the ph monitor recently and was researching a few of there other probes. I read hundreds of reviews and I didn't buy any of them. Way too many of the reviews complained about inaccuracies, and not ever being able to repeat the same result twice back to back. Also price on these is extremely high compared to something like a Hanna checker pen which has great reviews and about a third the price. So now I have the Hanna checker ph pen (and phosphate, all, and ca checkers) and am very happy and results have been able to be duplicated every time back to back so far.
Again just want to state I have no personal expierence just read hundreds of reviews on several sites.