420 kidder. I have run systems I built similar to that for a long time. You can run 24/7 I am currently doing that as an experiment, and I am quite pleased. However; I don't keep water filled all the way to the netpots...NO need.

I really like the results from running "on" for an hour, the "off" for 15 minutes. That will allow for oxygen availability. Like you want. These times will also allow the pump to cool and back-off any sediment that sucked up in the pump filter. In turn that will help the longevity of the pump.

Hope this helps. Search Aero and Drip threads for info from Zandor or myself, and that should answer more Q's. Goodluck

p.s. (It is a little harder to find good 15 minute timers.)
I will give you a hint. Go to pet store and get Iguana cage timer. It has 2-Light/2-Dark inputs, and 4-on all the time inputs. with 15 minute interval timer...For recirculating ghetto tub like you have...that is perfect.
You can run an entire grow room off one of these . They cost 28 bucks.