Thanks
I popped in an airstone and moved the powerhead a little. The fish are breathing better now (though still a little harder than usual). The clown is being very odd, but the Chromis and the goby are doing well.
I'll take the media out tomorrow. The Seachem website indicates that Matrix can be used in conjunction with Paraguard, so I'll put some of that in to give the nitrifying bacteria more to colonize.