Hi there,

Each L-port is intended to run 2 independent channels. It looks like you're trying to connect 3 pumps to a single port which is incorrect.

Each port should have a YL2-splitter connected to it. Off of that splitter you can have 1x Tunze1 cable and 1x Tunze2 cable. Since you have a total of 6 Tunze pumps, you will need 3x L-ports, each with the YL2-splitter connected to them.

The article here shows you how to setup stream pump control through 1-10V:
https://www.aquariumcomputer.com/kno...-pump-control/