In comparison to a 5 to a 10-30 there is not much difference between them. I run one that does 60 liters per minute , I would suggest you look
http://www.ebay.com/itm/COMMERCIAL-...379?pt=LH_DefaultDomain_0&hash=item4618d9a0cb . It does not have to be that big but that is the exact one I run. you can find ones that only do 500 ish gallons of air p/h for cheaper. Mine uses only 55 watts of juice and it will throw air like nobodys business

The more air you can hit the roots with the better the growth will be