Recirculating 3 gallon pots auto drip?

Hey everyone, I’ve put together a 4- 3 gallon fabric pot
Recirculating auto drip system. I’m going 50/50 coco perlite wanting to try autos in this setup. My question is how often should the pump run? I start getting run off in 7.5 minutes. 3 adjustable drips per pot.