Hmmm....I didn't even know that a stream rock even existed until now. That might be a great option for me. Thanks for the advice. This will really help me out.

You should be able to get Tunze Rocks for pretty cheap now since I don't think they work with the newly redesigned Tunze streams.

Stream rocks come with an adapter ring now that will fit every kind of stream pump except for the nano. - from the Tunze site.