Bought a house a few months back with a pea gravel crawlspace. In one corner is a sump pit with a corrugated pipe attached that is a gravity drain to the drainage ditch on the property. No pump has ever been in the pit. I cleaned the pit out due to being full of sediment and discovered the bottom of the pit had been cut off. The pit has about 4" a water sitting in it all the time do to the water table and the water level is about 4" from the drain pipe. I plan on putting a pump in the pit as during heavy rain the gravity drain doesn't work to well, likely partial clogged. Do I need to put a new pit in with a bottom ? I just added some rocks and a patio block to it today. From the patio block to the top of the pit is about 16" or so, do I need a deeper pit or will that just make the pump run more unnecessarily ? -Thanks