Thanks for the info....I think it is more "dirt" that hasn't settled. It's looking better the more my filter runs. The Boat...LOL....When my son was 2, he loved going to Pap-paws fishin' in his boats "playin' Fishin". So Pap-paw gave him one. We hung it up on poles in the yard, so it'd Rock and Roll as he played in it. He's now a teenager (the days of Playin' Fishin' are long gone.) It has a lot of memories.....So I kept it and added it to my pond. Maybe one day the grandkids will enjoy it...LOL....(I know...You might be a "redneck" if you have a boat in your koi pond. LOL)