a son t agro can be used for both flowering and grow, however the flowering only lamps give off a better spectrum for flower , mh are very strong and produce a lot of lumens! for growth only, i prefere to stick top cfl for grow and clones,its a little ,,alot less agresive, i want a slow growth for my sytem not long spaced internodes and branches, and then to an HPS greenpower flowering lamp! for max flowering.
the other reason i would stay with the cfl for growing is the running cost of an HPS or MH lamp for 18 hrs a day compared to the cost of cfl!, i stick all my HPS lamps to the 12 x 12.however if you want to grow big plants then go for two bulbs or just stick to the son t agro