Pool Renovation

[Yellowdog]

I've just had an old marcite plastered pool redone with Florida Gem (3M Quartz product) and new waterline tile. The pool was originally built in 1973 and I know little about the plumbing. I've never noticed suction from the main drain on the bottom, but the skimmer is an animal. I saw when the contractor drained the pool, there were 2 pipes at the bottom of the grate, but I only have one pipe coming out of the ground and connecting to my pump.
Also, my overflow drain measures about 3.5 inches above the bottom of the skimmer opening and in the past my skimmer started sucking air if there wasn't about 2.5 inches of water above the opening. Its been a constant monitoring of water level since we bought our house. When asked, my contractor seemed vague about whether this is normal and seemed to think I do have a bottom return, but I'm not comfortable.
I'd sure appreciate any help or advice from someone. Thanks.

[geeman]

on some older pools the main drain ties in with the skimmer line with a T underneath the skimmer itself with only one line going back to the filter. there are auto fill devices that hang over the edge of the pool that hook up to a garden hose to keep the water level up.