I thought I would pass along my experience with Hanna Instrument's Champ pH meter in case anyone was considering the purchase of one of these meters. Let me begin by saying, first off, that they are made in Mauriritius, wherever that it.
As I always use the same nutrient mixture, know the pH, and change the reservoirs frequently, I really do not have much need for a meter. That said, my son gave me a Champ meter as a gift for Christmas 2010.
I used the meter about six times and began getting erratic readings. Using the trim pot and both 4.0 and 7.0 calibration solutions I still could not bring the meter into calibration. I wrote to Hanna and after a few emails they advised me to return the meter to them. I returned the meter and they replaced it with a new meter on November 2011.
After about the same number of readings, less than a dozen, the new meter also failed, same problem. No amount of adjustment to the trim pot will bring the meter into adjustment. I wrote to Hanna again, as it is less than six months from the time they replaced it.
Hanna wrote that I should purchase a cleaning solution for the probe. Keep in mind that the meter has only been used a dozen times. In addition to the cost of the meter, you are expected to buy 7.0 and 4.0 calibration solutions, and now the probe cleaning solution. They also stated that they go by the original purchase date; so even though the meter came from them less than six months ago, the meter is out of warranty.
Consider the cost of the meter, the cost of both solutions, the cost to return the meter; then consider I used it for about two dozen readings and now I get to toss the meter in the trash. I responded to Hanna: that if there was to be a meter in my future, it would definitely not be a Hanna product.
Why would Hanna, who is supposed to be an industry leader, market a piece of junk like the Champ? My answer would be one word: GREED!
For the cost of just one of the calibrations solutions you can purhase a chemial pH test kit, like the one shown on the left. I think in my entire hydroponics career I have only had to purchase two kits.