Do ceramic bio rings ever get clogged and need to be cleaned out/replaced? Is there an easy way to tell they are not performing well besides spikes in ammonia and nitrite?
Pretty good question, especially the second part of it.
As said, if you have good filters before the ceramics they should go a good long time between cleanings.
Sooner or later they will need to be cleaned well. I`m not talking about a gentle swish in tank water, I`m talking about a bleach bath to get out all the organics that have built up over time. A guy could clean a portion of his media at a time so not to cause any disruption of whatever bacterial activity that might be going on in that media, real or perceived.
When that needs to be done is the “kicker”.
Probably a large number of people have bacterial activity that is larger in other parts of their systems than their media, and know what..no way to tell it`s happening that way.
Bacteria will find a way to live.
Either in the media or in the tank. Wherever it`s easiest to feed-n-breed.
If your media becomes a clogged up mess, the colony will become strong somewhere else.