GaryM expounded:

Thanks Ann. The trouble is to do that requires a significant area to
be raised too as the tank is in the middle of flat area of lawn.

Hence my search for another solution.

I hear ya, Gary, but there really isn't any way around it, my sister
and her husband had to replace their lawn because of it...luckily it
wasn't much of a lawn anyways. Typical contractor job over bank
gravel, 6" just wasn't going to cut it anyways. Good luck with it.
--
Ann, Gardening in zone 6a
Just south of Boston, MA
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