Basement toilet leaking - even after replacing ring

The house we bought about 10 months ago has a small bathroom in the basement with a toilet & sink and a plastic grinder/pump. Everything was working OK, but it didn't get a lot of use.

The toilet started majorly leading out of the base after one or two flushes. I replaced the wax ring - same thing. The toilet is on a small platform which is perhaps 6-8" high - so that it drains into the plastic grinder/pump box which is the type that sits on the floor - it is not embedded into the floor.

I suspect the float adjustment in the grinder/pump box, but my question is whether the wax seal on the bottom of a toilet is supposed to be completely water tight, and so in this case should be able to handle water in the toilet waste pipe as the grinder/pump box fills up, or, is the grinder/pump float always supposed to keep the level of the waste below where the toilet waste pipe enters it?

I don't want to lift off the toilet yet again and replace the wax ring again if I don't have to - so any advice on how tight the seal created by the wax ring is supposed to be would be most helpful. Thanks.