I have play sand in my 180...I don't really vacuum it. I run the python over the sand without touching it...it sucks up the debris but does'nt stir the sand.
I believe play sand is pretty non-reactive...meaning I don't think it does a thing to the water...not that I could ever detect anyway.
Quick note: While play sand is nowhere near as prone to clumping and compression as the finer types of sand are it will still need to be turned a bit once in awhile to keep from forming anaerobic areas. Hope this helps.