ummm... is this a new set up??? sounds like diatom troubles!! A couple of 25% water changes can be helpful!! Just be patient - things usually settle back into balance.

Maybe the filter elements aren't sitting in the filter correctly and the water is bypassing the filter? This is why all my tanks have at least 2 filters. Sorry I dont have any Wisper filters, can't give you any specific advice. Try to call Wisper, they may have an 800 #. People rarely call the manufacture, but who knows more about their products?

If I remember correctly the 60 has two sides and no bio wheels. It sounds like you changed both sides at one time (?) This may have blasted your bio filter and now you are seeing a bloom in bacteria in an effort for the tank to re cycle. Next time only change one side at a time. Did you also rinse the bio material in the bag ? If you do use water from the tank in a bucket. One of my filters has four and I change one every two weeks.