Tanks mang!

i am a happy user of this dosing pump as well. one question i have is with 3 rollers on the dosing head, the rubber line is always pinched at one or more points, so even without a check valve there shold be no possible way of siphoning happening or fluid motion of any sort without the dosing head turning, right?

I found out last night that without the valves my lines drained back into the bottles.

Good to know. Im using them to splice pieces of airline tubing together, but i will be sure to run them regardless from now on. thanks.