How often should I water in a ebb and flow system

I have been given so many different answers to this question that I am more confused then ever. I water ever hour for 4 mins while the lights are on. I am getting slow growth and am thinking I am water too much.

How often should I be watering.

Thanks

10 -20 mins for every hour

Ok. Thanks. But I have an auto siphyn and it takes about 3 mins to fill my tray and 1 min to empty. If I run it for 10 mins the plants see water for the first 4 then the pump just pumps water into the siphyn and the plants get nothing. Would this be ok or should I look into changing the syphin setup I have.

Thanks