You can't really do a siphon vacuum with sludge -- it's too heavy and solid.

I started to feel guilty, think maybe I hadn't suggested this:
If you can drain and refill for less than $120, it may be a good idea.If you can drain and refill for less than $120, it may be a good idea.
but I did, in my first post.

Is there a reason why you ruled this out? If you've got layered sludge on the bottom of an Intex pool, you are STILL a long way from cleaned up -- on an Intex at LEAST 10 days.