air bubbles in dosing line doser 2.1

[Nico F.]

I've bought a slave doser 2.1 with my SA + KHD unit.

I calibrated the pumps. But the first days my dosing lines seems to run empty into the sump.
So i placed check valves in the suction and pressure side of the doser.
Suction side is no problem, but in the outlet lines to the sump, big airpockets keep turning up.
I use the original GHL silicon tube, lines are about 1.7 meters long.
Tubing is pushed all the way up on the connection pieces.

With the airpockets in the lines, i can't dose precise amounts.
Should i place the checkvalve at the end of the dosing line or are there other solutions.
I never had this problem with my h2ocean P4 pro dosing pumps.
I would like to change everything to GHL if i get this sorted out.

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