How to penetrate the pool shell with replacement plumbing.

Greetings,

We're having pavers installed around our pool, which will involve removal of all the existing decking. While the decking is out, since I'll have easy access, I'd like to replace the plumbing and increase the pipe size from from the current 1.5" to 2".

I'm going to have the skimmer professionally done, but don't see the need to have a professional replace the return lines. I also want to add a dedicated suction line for a pool vacuum.

The one aspect of the work I'm uncertain of is how the plumbing is sealed where it penetrates the pool shell. I'll also need to drill a new hole in the shell for the dedicated vacuum return, which will also need to be sealed.

Any input/advice would be most appreciated!

One method that's been used successfully is to put a coupling or other fitting on the pipe at the point where it's embedded in the shell, and then grout around it with a high strength, low shrink concrete mix like Thorite (http://www.thoroproducts.com/pdf_appl/appl_thorite.pdf)

I'm sure there are many other methods that would work.