Recommended is 5 start, smoother transition but that tank should last a week or so I have mine on all the time. Depends on the kit i guess. I like the AEM kit(pump and controller) and I have a devils own nozzle and nozzle holder/checkvalve coming in today.My tank is 2.25 gal and lasts a little bit. But I went through 1 gal on the dyno tuning day12 psi start 15 max but I am still testing that.