I run no substrate in either sump nor display.

Ph 8.1-8.3 must be regularly maintained
Rest of Parameters are consistent

Pros - No sand particles getting into mag float and scratching glass, no sand storms, good flow under rocks, easy to clean, no place for nitrates to get trapped and build up.

Cons - PH stability, no extra places for critters to breed, less surface area for bacteria to grown on, detritus is more readily visible (this can also be a pro).

Daniel