While Mag pumps are loud, sometimes it's the Remora itself that's loud. Heres a trick I used from another site that works great.
This took maybe 10 min and requires household items.
Need:
-Plastic (I use #4, the lid off a cream cheese container)
-Air tube
-OPTIONAL – glue gun
Steps:
1) Take out the collection cup and dab it on a piece of paper, this will outline the aprox. size of the chamber as the 1st chamber is about the same size as the reaction chamber
2) Cut out the damp outline of the paper and stick it to your plastic, use it as an outline to cut out the plastic.
3) Take your air line hose and cut on one side across the whole length (which should be the total circumference of your plastic minus a little bit)
4) Cut the first to match the length of one side of your plastic, then cut 3 more according to how long you will need, you will need a little less then the total circumference as the with will take up some space on at least 2 sides.
5) Test the square with hoses around the edges for fit in the hole; you want it tight so it should bend a bit along its width, but not too much. Trim the length to fit and the width so that it will bend when in place.
6) OPTIONAL, I chose to use a glue gun to keep the air tube edges in place; I glued the top side only so that the glue won’t be in contact with the water as I don’t know if it is harmful. If you make your lengthwise cut along the inside of where the tube naturally curls it will stay on without glue though.
7) Put it in place and clean it when you clean your skimmer
I have mine hooked up to a Mag5 in my livingroom and a can barely hear it with this little trick
Thanks to Drez over at AquariumPros for the idea.