I don't know if someone already suggested it but I use G.E. Daylight F20 lights from Lowes. They are only $6-$7 which beats paying $20+ at the pet store.
specs:
F20T12 (fits T8 socket)
20W
6500k
1025 Lumens
In my 30gallon I have 2 Cryptocoryne wendtii (1 currently trying to propagate)
2...