hi, i want a planted tank and atm only hae 1WPG. this is not enough of course! so, i am going to get another tube and ballast etc. probably from lamp specs. all i want to know is, in terms of growing plants what is the difference between the £13 tubes in my lfs and the really cheap ones on lampspecs? i thought plants just went on amount of light, so surely i can go for the cheaper option? any help will be invaluble. Ty. 
