Using a PMUPv2 with a Kalk reactor

[defasum]

I will be setting up an avast marine Kalk reactor and want to use a PMUP with an FMM module connected to my apex to control the dosage. I have connected the PMUP to the FMM. connected the FMM to the apex. I see the new tiles show up on my apex but when I turn the tile to the ON position the PMUP doesn't come on.

Does anyone have any idea what I am doing wrong?