I run a 10 gallon sumpless system which is shared between sps and lps. I do 60 percent water changes to upkeep my calc, alk, and mag to respectable levels. I run a skimmer, macro algae, vodka dose, and run GFO to reduce phos and nitrates. A 30 gallon should be manageable without a sump if you are willing to put the effort in, sps are quite demanding!

Heres my link you can see the type of equipment and maintenance I do/use
http://www.nano-reef.com/forums/inde...owtopic=290971

this was my old system, sumpless and HOB equipment and mainly SPS. grew them like crazy

http://www.nano-reef.com/forums/inde...ic=140795&st=0