I have a full basement with a typical drain tile installation (I believe the builder installed drain tiles inside and outside the base foundation wall). The drain tiles empty into a sump pit contained in the basement. We have poured concrete steps out of the basement and at the base of the steps there is a drain that also carries water into the sump pit (this is below grade so the builder had few options to get rid of water that accumalted at the bottom of the steps). When the plumber cut the opening in the sump pump pit for this drain (4 inch PVC) he was less than precise. Due to this "rough opening" we now have a rapid rush of water entering the pit around this 4 inch PVC pipe (water that accumulated below the concrete slab). This causes my sump pump to cycle far to often (about every 30 seconds when the water table rises). I have never seen any water coming from the drain tiles emptying into the pit so this rough opening is probably relieving much of water pressure under the slab.
My question is, should I seal this rough opening and allow the drain tiles to capture water and ultimately bring it back to the sump pit? If I should seal the rough opening what do I seel it with? Can it be done under water? With our very wet summer and fall and the sump pump cycling so often I'm in danger of pump failure very often. I've already plumbed a battery backup and replaced the typcial manual float swith with an electronic high/low water sensor (attempting to eliminate the mechanical swith failure).
Any help would be greatly appreciated.