How big of a tub for 5 plants in DWC

Title pretty much says it all. I'm going to Target today to buy a Rubbermaid bucket, just wondering how big of a resovoir i need if I want to grow 5 plants in 5" pots.

Thanks.

I would go with 5Liters per plant. (Remember that the water is only filled up to 1" bellow the net pots, So you will probably be looking for a 40liter Rubbermade as you can only use around half the space.
To a piont, I would say, "bigger the better" it is easyer to control PPMs, PH, and Temps in a big Rez.