i have seen good flourescent grows, especially with the compacted floros. IT may be the strain you are growing that makes it so compact and small, prolly majority Indica. Are you using a CO2 tank, generator, or CO2 tabs? Usually when you put CO2 in the room, itll make those plants nice green and tall, from my experiences with CO2 n e ways. being that they are 8 weeks old, Im surprised they arent at least a foot in height. Id say switch out the floros with the hps, and notice how much faster theyll grow under the hps. you could combine the Floros with the hps, but the floros would be insuffiecient for how much light intensity the hps would put off. You should just put ur plants either on 18/6, or 24/0, because having only 4 hours of dark is basically worthless for the plants. Good luck, and post me back with results!