4'' carb stone big enough for 7bbl batches

[jcmccoy]

http://www.gwkent.com/pico-carbonato...h-tc-15in.html

Is this stone big enough for a 7bbl bright tank?

it is 4''

If not what size should we get?

[Thirsty_Monk]

Yes that would work.

[UrbanPoison]

We use a 6"stone in a 10bbl carbonator and it works perfectly. Your 4"will work fine.

[Greenbushguy]

Surface area

Bigger is better with carb stones. Yes your stone will work but a bigger stone will get it done faster. It exposes more surface area to CO2.