also, couldnt I drill into a side - 2" below the waterline? this way, if the pump was having issues, the worst that would happen is the waterline would drop and the sump would fill up. passed the "dry" media.
http://www.boatersworld.com/product...iplumbing-fittings-valves;civalves-thru-hulls
http://www.boatersworld.com/product...iplumbing-fittings-valves;civalves-thru-hulls