submersible water pump for single bucket hydro grow.

I have a one bucket hydroponic system that someone with experience worked up for me. It holds four gallons of water and I am going to put the pump in the same bucket that I am growing in. What kind of pump should I get as far as GPH goes. I don't want to overpump the water or have it be to weak. Thanks for your help in advance.

Just pick up a generic small fountain pump from Home Depot. Most have a volume adjust by the impeller so you can choose how much or little flow you want.

http://www.homedepot.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10051&productId=202017048&langId=-1&catalogId=10053&ci_sku=202017048&ci_src=14110944&cm_mmc=shopping-_-googlebase-_-D28X-_-202017048&locStoreNum=6643&marketID=48

Look on the side of the pump (like the pump in the link above), there's a dial to control your GPH