Aqua Medic Reef doser help

[Tasmanian]

I am dosing Randy's 2 part with a Aqua Medic Reef Doser. It worked great for a week. Then I went out of town (of course that's when it acts up!). When I got back the Cal was still dosing fine. The Alk had dosed the entire gallon. I reset everything and regreased the hoses. It worked fine yesterday. Today once again the alk just kept dripping fo a total of about 3/4 gallon. The motor shuts off but the liquid just keeps dripping out.

Added info:
-I am dosing out of 1 gallon jugs with two holes in the cap. One hole has a 1/4" hard tube going down to the bottom. This one has the flex tube going to the doser. The second hole has a 1" piece of hard 1/4 tube in it to let air escape. I have done this for both the Alk and the Cal gallons.
-They dose into the sump. The gallons are higher than the sump.
-The Cal side is set up exactly the same but stops dripping once the motor shuts off.

Any ideas?

 

[A.T.T.R]

aqua medics dont stop the flow when they shut off
you need to have the output higher then the input and use several check valves to keep the fluid from flowing back into the storage tank and loosing its prime ( it will get the prime back but it will take more time and end up dosing less then you want it to

 

[Tasmanian]

Ok thanks. I wondered if it was simply continueing the siphon but I wasn't sure since the Cal would stop. Perhaps the Cal hose was just a little tighter or something and so it would pinch off.

I look for a few check valves and and reposition the set up.

Thanks