Help Improveing Water Reflection Effect.

I could use some Help improving this water ripple effect. here is what I have so far

Some constraints for the out put are:

  1. must start and end in complete blackness
  2. must be on a perfectly black background.

What I have is a great start but the following things could use improvement:

  1. there is a slightly square look to the ripple rings
  2. there seems to be a dark strip going thru each ring.
  3. The each ring seems to wide, it dose not fade in to a sharp line like in a real reflection.

The Reflections will be projected on to a Stop Motion animation set.

Here is the blend File:
make rippels.blend (5.55 MB)

Any suggestions?