Hey guys its summer here and temperatures rising as high as 43 degree celcius.. coolers are out. i have a simple plan in mind for saving energy and water usd for coolers. ours is a cooler using 60 L of water in 4-5 hrs. and the water is carried on from a lower tub to an upper tub for draining it on to a special grass fixed on the walls. now this requires a pump of 50 watts at least. and it consumes more energy and water if running continuously. so i am thinking of designing a circuit that would switch the pump on for 2-3 min every 15-20 min. at other thimes it would be off. any ideas??