I have one. As long as your dosing container is close to the pump they work great. I tried to use one pump for kalkwasser. I set up a 5 gallon bucket about 8 feet from the pump & it wont prime. I dont know if more expensive units are capable either though.
How long have you had it running? How's the accuracy? My plan is for CA/ALK and top off. Though I'm not yet sure if it will work for topping off. I go through almost a gallon a day. What is the max ml per hour oh and is it quiet?
I have not had it running very long. As far as using it as a top off, your reservoir would need to be close. I wanted to use a 5 gallon bucket but cant put it close enough for my setup so i am using a gallon jug. Its not silent but not too loud either. Dosing pumps are expensive. For the price, I am very happy.