My swimming pool is 4 feet deep at the shallow end and 6.5 feet deep at the other end. I am thinking of pouring concrete to make it all even. Would anyone know if the floor and walls can take the extra weight ?

I doubt anyone could answer your question without knowing how the pool was originally constructed.

Without knowing how the pool was originally constructed, I have worked on projects in the uk where this method were used.with great success to shallow out pools.

http://www.lytag.com/applications/structural-concrete.

I seem to remember that on part of the project polystyrene blocks were used as well . big ones specially made at the time covered in mesh and sprayed with concrete.

So to answer your question it can be done but using specialist lightweight materials, the secret would be to replace the weight of water you will be reducing it by with the same weight in materials.

It won't have to be structural as the the original pool shell will be the structure you are just looking for an in fill that you can tile and will support the weight of water above it without moving.

A good civil engineer should guide you in the right direction as you will need help with calcs etc to determine rebar sizes mesh size and how tie into the existing structure.

Is it worth all the hassle there will not be that much of a saving in terms of chemicals etc unless you are talking of a 25m pool

The forum sponsor may have a better idea give some consideration to contacting them.