Going from sand to BB

[Rikko]

Hey all,

I'm thinking of going BB - I'm sick of the crap growing on the sand and the hair algae that I'm sure isn't helped by the nutrient sink that is my shallow sand bed.
I'd like to pull the sand out over the next few months but was wondering if anyone had done the same and had any pointers.

I'm mostly concerned about rockwork shifting now that the sand isn't there to help keep the base of the rock a little more stable.. Does anybody/everybody who goes BB put anything on the bottom to prevent pressure points, or is that just an overcaution that isn't an especially big deal?