watertank base- timber v concrete

[zongatron]

Hey guys,
Im putting in a 13000l water tank. the consensus seems to be that a timber base is better than a concrete one.
Their is about a 20degree slope where i am placing it so I will cut into the hill a bit to level it out.
Q- As there is quite some weight in this much water I am unsure as to how to build the base in timber. Do i just lay some solid bearers along the ground at 30-40- centres so the ground takes the load (room for movement?) Or do i dig in some low posts then fix bearers to these?
With a timber base, i am also a little concerned about rot and white ants. Being a water tank i never really want to shift it to repair the base. This is mainly why i was initially going with a slab base.
Another option, could i lay the slab then simply fix timber decking to the slab without bearers or joists? (rot?)My reasoning in this is for air circulation beneath the tank itself..
i dont think it would be the go to lay slab then bearers then joists then decking. Seems a bit crazy.
What do you venerables reckon ay?
Thanks

[Larry McCully]

You could use a joist and bearer system with a layer of 15mm Compressed fibre Sheeting on top to support the tank. http://www.jameshardie.com.au/Produc...tAreaFlooring/

[bricks]

Why not a sand base?

[zongatron]

The builder wont warranty the tank if i place it on a sand base. He also reckons problems walking over the sand when trying to place the tank in the right spot...