harmon writes:

I have to drain the pool a little but am asking what type of cement to
use to repair this crack as it will be exposed to the pool chemicals
though most of it is above water level. none of this is the actual
swimming pool, it's the small round hole outside the pool wall, about
1 foot away from the wall of the pool and exists only for the top
suction line into the pool pump

What you are describing sounds like the skimmer niche.

Just use tile grout from Home Depot/Lowes. You can get a small quantity.
Use sanded type if the crack is larger than 1/16", unsanded for thinner
cracks. Variety of colors if you don't need just white.

See my page:

http://www.truetex.com/pool.htm