I too am looking to do the same. I already have the pool fill valve hooked up to my sprinkler system that is controlled by Irrigation Caddy. I can start programs on the Irrigation Caddy easily via http, so creating a "fill pool" scene will be easy.
I am mainly looking for the float valve to trigger the scene. I will use PLEG to start a timer whenever the sensor/float valve is tripped. Say, 5 minutes tripped. This will filter all all the false-positives from the kids splashing around. I have an in-ground pool, and would prefer to put the float valve in the skimmer.
I am considering the possibility of simply placing a Honeywell 470 Water Flood Sensor Probe connected to a the normally closed loop of a Honeywell 5816OD wireless sensor. When the water level falls, the loop opens, PLEG timer starts. When timer passes 5 minutes, or an hour, or whatever, the "pool fill" scene will be triggered that will add water for 10 minutes. I suppose I could also cause it to turn the water off early if the circuit closes again.
Has anyone done anything similar successfully?