Oh wow so it's the light modules that put you over. My main tank is on AI and they of course they have their own controller. My seahorse tank has LED but it's plugged into the PC4 so my lights at most take up 3 plugs on the PC4. I have SL1s on each tank for Auto Top off on the seahorse tank and for kalk(pH monitored) top off on the reef tank. ph probes are on the SL1 as is the float switch that's on the ATO. So three modules on each tank for me. Maybe I should add one for something lol