ebb and flow ?s

ok... did the soil grow now its time for the ebb and flow... but just a few ?s

i'm getting a 3' x 3' x 7" white tray
using (20) 5.5" kord pots and hydroton grow rocks.

what size reservoir should i get? 30 gallons? or 25?

what size water pump? i'm confused but i'm thinking maybe a 250 GPH?

also do i set it to flood the tray every hour? and it should fill/drain the tray in a matter of 15 minutes right?

It takes 18 gallons of water to flood a 3X3 tray

ok thanks bro.

what about a water pump what GPH should i get? the tray will be sittin prolly a little higher above it so i will be able to pull the reservoir out whenever needed.

and about floodin.... every hour? and it should only take 15 min to flood/drain right?

nevermind found a webpage that answers everything pretty much from GPH - reservoir questions.

Build Your Own Hydroponics System | BGHydro

for anyone else who was possibly curious.