Water Supply Valve

Hi, I just finished updating my pool with an inground autofill pool system. I turned on the anti-spihon valve and it was leaking. I purchased a new valve and it said that the valve should not be used in operation where the water is left on for more than 12 hours. I planned on leaving the valve on (slightly opened) full time. So now I am thinking that I may have the wrong type of valve in use here. I know local ordinances my differ, but what is a safe and effective valve to use to supply water constantly to the autofill system?

Thanks,

Bill