Living Air XL-15 Classic - Foul odor!

About 6 mos ago my unit started to emit a foul odor. It smells organic like a lake or something. It isn't constant but I can't get it to go away! I bought new plates and filters since mine were pretty old. I have cleaned it thouroughly with alcohol and nothing worked. When I put a new clean plate in, it smells ok for about 2 mins then it starts to smell. HELP. I know sometimes the ozone can react badly with somethings (like Paint fumes) but I can't imagine what it could be reacting with, nothing has changed in my home. My house stinks and its embarrassing!