This may not be the right place to post this but here goes. The liner in my 18 by 36 ingound pool failed because of poor installation by the previous owner of my home. I hired a company to redo the bottom and replace the liner. To resurface the bottom they basically just mixed sand and portland cement(no water), spread it with hand trowels and then sprayed wate on it and put the liner in. It is the lumpiest most uneven bottom you can imagine. What is the proper way to do this? Also is it possible to drain the water, remove the liner, smooth the bottom and reuse the same liner?