I am prepping a base for my hot tub. First I am placing a geotextile fabric, then 6" of compacted aggregate, then 1-2" of mason sand for leveling, then 16"x16" regular concrete blocks (cheap kind). The hot tub will go right on top of the concrete blocks. Does anyone with experience recommend using edge restraints or polymeric sand? Note: There will be an extra 3" on all sides of the tub to the edge of blocks. Thanks in advance for your help.