Pink foam between tank & stand?

[Prospec1]

What is the reason for putting the pink foam between the tank & stand?

 

[subREEFed]

Some people do it so the tank stays flush on top of the stand. So if the stand has any imperfections (wood) the foam will fill in any voids. It kinda acts as a suction cup too, Plus insulation. alot of it is preference

 

[Toddrtrex]

Used for acyclic tanks, and not glass ones with the rim.