Replacing hydrostatic valve

[jerryls]

I have a concrete pool and had to drain the pool to replace the brass hydrostatic valve that was 30 years old and leaking. The new valves made by Hayward(SP1056) are PVC and screw into a 1.5" fitting. I chipped out the old valve and I want to put in a female fitting into the main drain to accept the valve. My question is, what do I use to hold it in- two part epoxy or hydaulic cement or what?
Thanks

 

[JasonLion]

You may need to replace the entire main drain fixture. Can you post a picture?