ok i got a 55 and some salt water equipment from a trade in, right now ive got a 15 gallon sump and a really big protein skimmer runnin with fresh water but i need aq power head equivelent too 1100 gph i havent seen them in stores and dont know where to get one, another thing is, what is the salinity that i need my tank to be to add live sand and live rock???