Hello and welcome to the best place for pond info available. Others that know much more than I will be along shortly but for now here is something to consider. With trees all around you surely have a bunch of sediment built up, that was what got stuck in your trunks. You should start researching aeration but be sure you have the right system and know how to start it properly. Good luck and keep us updated as you get more and more addicted. Bob-O

Do nature a favor, spay/neuter your pets and any weird friends or relatives.