A lot of outdoor concrete slabs / patios have a slope for drainage. If you put a hot tub in such a location obviously it would also be out of level.
Is there any standard or recommended way to level the slab base prior to installing the hot tub?
I have scanned around and there are numerous internet suggestions - but ideally I'd like to know if there is either a standard "best practice" method and/or something recommended by hot tub manufacturers.
Examples of suggestions I've read each of which has some obvious potential but maybe avoidable problems:
Shim with angled bits of wood (susceptible to rot, movement)
Sand (could move/erode)
Build up additional concrete (poor bonding, spalling, etc.)