as far as coralline growth you may want to look into dosing kalwasser. This would raise the calcium levels and promote coral and coralline growth. You wouldd add this trhough a drip system with R/O water during top offs. You can also look into Nielson and Kalk reactors more expensie but you set...
I would just add sand for a dsb. The sand should already be live if it is from an established tank. You may want to look into alternatives besides live sand since sand inside will seed anything you put in and eventual make it live. Your money would be better spent getting for example Yardright...
I have a 90 Gallon and run 2 x 175 Halides and 2 x 96 power compacts for 542 watts. I too ran into many problems when I first set-up my tank albiet a smaller 30 gallon and have found that lighting is something that you cannot skimp on. Good luck
