Do you have white, stringy stuff in your tank that looks like this? It could be caused by the Spaghetti Worm (Loimia medusa).
Keoki and Yuko Stenders' Spaghetti Worm Photo
Top Marine Worm Photos Gallery
From Stan & Debbie Hauter, About.com
Keoki and Yuko Stenders' Spaghetti Worm Photo
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