Greetings one and all... Just a little sharing here today.
Here is the media I used..filter foam for a fish pond (HOME DEPOT) $5.00 enough for 12 !! LOL

Here is how it is installed.
Cut in a circle with a hole for the intake tube, inserted approx. 1 and 1/2 inch from bottom of intake chamber...just above intake tube.
notice the pumice stone I used for a silencer (works great)
It works very well this way. Granted this may only be a solution to these cheaper Odyssea brands...but who knows I just thought I'd share my success.
so far so good....

No bubbles except after cleaning, then just a bit for a few hours.
Have great day !!!