Bio Filter Maintenance

Question
We moved into a house ~1 1/2 years ago that had a poor 150-gal saltwater aquarium.  Due to the fact that it wasn't set up correctly (no refugium!) and we had zero experience we immediately converted it to freshwater.  The plumbing is homebuilt; one canister holds a mechanical filter and the other we're using as a bio filter.  Per the local aquarium's recommendation we packed ceramic beads and ceramic 'grass' into the bio canister which has worked well for the past 1 1/2 years.  The advice we were given was that this ceramic stuff should never need to be changed out; however, my pump has been struggling recently and the circulation has slowed down to a trickle.  I've eliminated clogged intakes, mechanical filter, and everything else as a culprit to the slow circulation, but I'm wary of opening the bio canister as I know it can throw off the water chemistry (and we have about 90 small fish in the aquarium).  Does the bio filter actually need to be changed?  If so, do you have any advice for the procedure?  Appreciate any help you can provide.

Answer
Hi Dave;

Over a period of time they do get clogged up with organic waste. Just open it up and gently rinse the media in a bucket of tank water. This will preserve most of the beneficial bacteria but will hopefully get the crud out enough that it will run properly again. Check all the pipes and/or hoses for accumulated gunk too. If that doesn't help, your pump may be getting worn out and need to be replaced. Hopefully it's just dirty, a simple fix, and it will be running again in no time.

I hope all goes well...

At Your Service;
Chris Robbins