switching to what, crushed coral?
that's a step backwards. CC
traps detris, is hard to vaccum, so you end up with high nitrates all the time.
plus any sand sifters are going to get scraped up by it.
your power heads should be angled slightly up, as to agitate the surface of the water to improve gas exchange. that should reduce direct bottom current and stop your sand blowing.
I have 2 MJ 1200's in my 40gallon (only 3feet long, instead of 4feet like your 55g) and my sand si fine, unless the MJ comes un-suctioned.