Just signed a contract to get a 18'x36' kidney shaped vinyl lined IGP installed in the spring. We can go anywhere from 3.5' to 8' for the same price. We are leaning toward a sport pool as we have two girls 2 and 4 and will be doing our share of entertaining as well with adults. Thinking volleyball net in the middle perhaps. My initial reaction is 3.5' to 5.5' to 3.5'. this will result in a water level of 3' x 5' x 3'. It seems a little shallow. Let me know what you guys have done and if it works or if you would tweak it if you could do it all over again.