really? i've had their ph monitor for a year or so. never had any issues with it as long as i use 'quality' calibration fluids. i use it for constant monitoring as well and works like a champ. their support is top notch as well.
as far as the calcium monitor - it seems like a lot of work. it's not recommended for constant monitoring but for sporadic checks. the method they recommend to use it is the 3 shot glass routine. 1st shot glass has the 100ppm calibration fluid, 2nd shot glass has the 1000ppm calibration fluid, 3rd shot glass has tank water. let all 3 come to room temperature. use the 1st solution and calibration, 2nd then the tank water. let it stand for about 2 minutes to get a reading. also a 9 volt battery only lasts 150 hours in the unit so the 9v adapter is recommended.
i can buy a lot of salifert calcium test kits for what the calcium monitor costs.
The concpet is great but I dont know if it is that reliable. A friend bought one and couldnt get it going so he brought it over here, and I have been playing with it for a couple of weeks. The low flow is a for sure, any flow at all and its all over the map. even in the low flow it still bounces, I dont think it is something I would rely on.