Not sure this will help you, but I am powering my 12v pool light using a 24v relay connected to zone 6 of my controller. While it is just one color, I would imagine you could program the zone to go on and off in quick sequences to get the color you want? I mounted the relay in the transformer box for the light and ran the two wires back to my sprinkler value manifold where I had zone 6 wire unused. I am breaking the existing switch to the light with the 110v relay contacts to control on and off leaving the switch in the on position all the time now.