There are 3 lighting outlets, one heater outlet, and two 'always on' outlets. If you want another piece of equip. to turn on off based on specific params then you need to give up a lighting out let. You can monitor PH/ORP no matter what, but if you want somethign to turn on/off based on PH/ORP levels then you need to give up a light...
Looks like these quotes cover it...
It is well known that a consistent lighting schedule is beneficial to the health of your animals. The Lighthouse controller can turn three sets of lights on and off at any time of day or night. You can use these three lighting zones for Metal Halide/Actinic/Refugium, or power compact Daylight/Blue/Moon light, or any combination you need. In fact, you don't even need to use the lighting outputs with lights. For example, If you wanted to run your protein skimmer only at night, you can use one of the lighting zones for that.
The Lighthouse Controller can monitor both PH and ORP on a continuous basis, and can be used with PH or ORP modifying equipment (i.e., an ozone generator or calcium reactor) to control PH or ORP. One of the lighting zones can be designated for ORP or PH control. Basically, when the PH or ORP value reaches a certain level, you can turn equipment on or off. If you use this feature, you give up one of the lighting zones, because the same plug on the AC strip is shared between one set of lights, PH, or ORP control. If you just want to monitor PH and ORP so the values continuously show in the display, you do not need to use the control feature and you can keep all three lighting zones for lighting or other uses.