Any doser could potentially be a disaster waiting to happen. I have a Pacific Sun Kore 5th doser...(5 pumps) and everything was fine after initial calibration. After a few months 1 of the 5 hoses leading off the dosing container got clogged and as such the doser was not working properly. I unclogged the hose but did not recalibrate thinking everything was okay. The next day the doser dumped a whole container (1800ml) of trace elements into my system (330 gals in total) within 2 hours, (the normal dose is 4ml per day, 6 days per week). I was at work. Luckily, I was alerted to this since my wife was home so I left work by lunchtime. I still lost ALL of my tangs. So the moral of the story is that even so called "better" equipment can fail if the proper precautions are not taken. I no longer keep my dosing containers FULL....I keep them 1/4 to 1/2 full depending on what I am dosing. I dose: Vinegar, Trace Elements, Potasium and Magnesium. I have a calc reactor so I don't dose Calcium/Alkalinity.
This wasn't the first time this happened...when I first setup the doser....one channel dosed almost the whole container of Vinegar, (no adverse effects to my animals/system). This was due to a siphon effect that occurred because I hadn't properly drilled out the cap of my dosing container, leaving enough space for air between the container and hose.