How many HPS watts? 4-5 feet is about the maximum range for a 1000w HPS. For a 400 watter, perhaps 3 feet maximum. Beyond those ranges, very little energy is available to promote photosynthesis. Like trying to light a joint from two feet away. The flame is hot enough, it's just unusable at that distance. Plus, the heat will dry-out the medium much quicker, especially in the smaller cups.

Fluoro's work fine, and some prefer them in early stages. (rooting clones, developing seedlings) Easier watering schedule and easier on the seedlings.

A picture would help.