I currently run a bubble magus Z5 on my RSM 250 as well. Also no issues, you will just need to put live rock or something else at the bottom of the skimmer compartment for the Z5 to sit on otherwise it will be too low and constantly fill with water.
@koganm can you please post some pics of your RSM 250 with the Z5 skimmer in it. I would like to compare it how mine is situated? Or instead of hijacking this thread, maybe we can just PM? Im always looking at ways to improve what i have and i like comparing things especially if its running the same equipment.