On one of my tanks I run a GHL, which cost a lot of money, although it is very easy to use and seems to be reliable, as I haven't had a problem with it for about 3 years. On another tank I am running a cheap chinese doser, this unit has run seemingly without incident for the last 4 months, the only downside to this unit is that it is a pain in the *** to program. It requires you to program each individual dosing times, which I find rather inconvenient considering that the interface to program the times is tedious.