As fishyfanatic said, have you cleaned the metal rods on the biowheel? Do not clean the fins, since they contain the bacteria. When mine start to slow down, I clean the metal ends and the little yokes on which they sit.
Freedom is the sure possession of those alone who have the courage to defend it. -Pericles
Let every nation know, whether it wishes us well or ill, that we shall pay any price, bear any burden, meet any hardship, support any friend, oppose any foe to assure the survival and the success of Liberty -JFK