I'd like to second the opinion about vermiculite/cement. Vermiculite and cement is water permeable (water can drain through). Although we built our pool ourselves, we did hire out the finishing because of the time factor: we had to get the bottom finished and the liner in before winter).
In any case, what we did after the vermiculite/cement, and I assume the same would be possible with sand/cement, is we sanded all the rough spots and trowel marks, we vacuumed the entire bottom, and we cleaned it with damp towels. It sounds like a lot, but it took less than a day. Our pool is an "L" shape -- 44 x 20 rectangle with a 10.5' deep and a 16 x 16 forming the bottom of the "L," which is to say that we had a huge area to clean up. It was worth every minute.
I've heard a lot of complaints about hills and valleys, but I can attest that we have one minor footprint and one little dip -- that's it. Otherwise, our pool is at smooth and as flat as a gunite pool. Another do-it-yourselfer suggested it and said that not doing what we did was his only regret.
Although we did not use get vermiculite from Schundler (couldn't get a distributor in our area), this site has a lot of information. BTW, we mixed our own (1/2 bag of cement to 2 bags vermiculite) rather than getting the premixed stuff (pool crete). It was a lot cheaper.
http://www.schundler.com/swim.htm
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