sump pit/pump

[paleon]

I've a full-size basement approximately 1,600 square feet. The house is 33 years old.
The only available sump pit is 16 inches deep and its wall is a cement cylinder (no perforrations to allow water to come in through the sides). I was told i've a floating basement. Given this scenario; please someone explain to me what is the correct size and construction of a sump-pit appropriate for the size of my basement. The basement is relatively dry but the sump pump is going constantly and there is ocassional wetness , especially during May & June (I reside in New Jersey)where the walls and floor meet, in the perimetry.
Subsequently this prevents me from finishing this nice (7 1/2 feet high) size basement.

[Basement MD]

There is no standard size or number of sumps a basement of your size should have. Usually the conditions of a particular home dictate the type of systems, number and size of pumps to be installed. However most sump liners are perforated and are aprox 22" deep by 19" round. The best thing you could do is to call your local Basement Systems dealer for a free estimate.