(03/25/2006) - I've used this CO2 controller for 4 years. Just recently, the display stopped showing the correct value. However, it still turns on and off at the correct pH points. I have verified this using a separate pH monitor. There is a very large downside to this controller. It requires a 0.2 swing in pH. The pH swings 0.1 below and 0.1 above the set point, creating the 0.2 swing. This is a large swing value and could mean the CO2 saturation level will be below or above the desired CO2 ppm 1/2 the time it’s controlling the injection. For example, a KH of 7 and pH controller set to 7.0 and 7.2. CO2 saturation will swing from 13ppm to 22ppm. 25ppm can be stressful to fish and below 17ppm is less than ideal. If you could limit the swing to 0.05, this would allow the controller to maintain CO2 saturation at 18ppm to 22ppm. This would be perfect. However, the Pinpoint controller does not offer this. The controller requires the CO2 saturation point down to 13ppm before turning back on, due to it’s very large swing value. I called Pinpoint years ago when I first purchased the unit. They offered no solution in reducing the swing value. All in all, it has been a decent controller. I would recommend it to those who need a cheap controller. If you’re looking for optimal plant growth, I would highly recommend purchasing a different controller with a smaller pH swing value.

(06/01/2004) - Very good product! The only drawback is that the PH has to fluctuate by .1 when dosing CO2

(01/18/2009) - Throw away your colormetric pH test kits which leave you guessing which color is closest to your water sample. This monitor is accurate, reliable, easy to setup and easy to calibrate. If you're serious about your water params then this is a must. Remember to buy extra calibration fluid.

(11/14/2007) - i tried several test kits and other brand monitors and by far this i have found is the most realible so far . keeping more than one marine aquarium at a time is tedious enough without having to keep doing so many water tests all the time . this has not only saved me time - but money on test solutions - but gives me peace of mind knowinging i'm using the best equipment i can . buy extra calibration solutions also people !!!! combined with the temp monitor .......i feel a lot more confident now than before. go battery powered also - adapter is a bit agrivating and really not needed ....

(11/10/2007) - This is a great monitor! Works perfectly with a 9 volt battery, but don't ever use the ac adapter with it! I bought the ac adapter, and it went nuts! The adapter causes interference, and gives a totally inaccurate reading.

(03/29/2005) - Throw away those unreliable and inaccurate colormetric test kits. This item should be on everyone's list of "needed" equipment and definitely a MUST have if you dose Kalkwasser.

(07/11/2004) - Only complaint is it's a tad tedious to calibrate. It says to submerge probe in fluid 1 inch but I put the fluid in the smallest container I could find and it was still only about half an inch or so deep. Definantly order extra calibration fluid, 7.00 and 10.00.

(06/01/2004) - Very pleased with performance. Accurate to +/-0.02 pH Easy to calibrate with jeweler's screw driver. Calibrate monthly and replace probe after 18 months per manufacture's recommendation. You should order extra calibration fluid when ordering monitor.

(06/01/2004) - I have now been running this unit for about 6 weeks. It was very easy to setup and configure. It is far more accurate then pH test kits.