GHL Profilux Standalone Doser

[Canadian]

I just discovered that the flow rate varies considerably depending upon how long the tubing is on the intake side. The values I reported above were with the intake tubing at 22" and when I re-calibrated pump 1 with 13" of tubing on the intake it was 47mL/minute.

I guess I'll just have to set up each pump in place with the tubing laid out the way it will be once everything is operating and then re-calibrate. I know the instructions say the "tube on the intake side should be short", but is there a length that is considered too long or potentially too stressful for the pump to draw the fluid up?