Microbubbles is a problem in mce600. Even u use sponge n filter sock.
I even diy a bubble trap but bubbles still there, only minimized.
I did a lot of experimentation but to no avail. I hv one
more experiment to do to attach a tube in the output of the
pump to raise the level of bubbles out.
One thing to note, if u plan to use filter sock, rinse
it first else ur skimmer will produce bubbles like crazy.
Pls let us know d result in your case.