Tourgy
you did very well to purchase your tank from waterstore. They would have to be one of the most professional organisations I've had the pleasure of dealing with. I actually rang them after I got their tank siting instructions and asked if it was ok to place tank on concrete rather than sand. Their man told me no worries at all. Tank been in for 5 weeks now and filled it to capcity just last night
Concrete pad I laid still showing no signs of cracking under weight.