Tropical Fish Central

Early on, I made the jump from hang-on-the-back (HOB) filters to canister filters.  They are much more powerful and can be mostly concealed in cabinetry.  I standardized on the Rena XP series of filter, and now have 3 XP2′s, 2 XP3′s and an XP4 across 4 tanks.

I started out with a pretty standard media configuration that looked like this:

I found that after about a week, the filter would be trickling water out.  I figured out that the white “water polishing” pad was becoming totally clogged within a week.  I put up with cleaning or replacing the pads every week or two for a few months, but grew tired of the hassle and cost.  I stopped using the water polish pads altogether, leaving that compartment empty.

The next thing to start causing me problems was the activated charcoal bags.  There was not a good way to clean those, and they’re pretty expensive.  I was needing to replacement about every other month.  That was too much.  I knew from previous reading on fish forms and other sites that activated charcoal only absorbs chemicals for a relatively short time, and then just becomes a place for beneficial bacteria to grow.  If the only advantage I was gaining is a place for bacteria to live, I could accomplish that without the expensive activated charcoal bags.  So, I bought some Seachem Matrix media – this stuff looks like small white rocks, and filled the top compartment with the Matrix media, which looks like this:

After this change, the filters would go 3 or 4 months before slowing down to the point I needed to clean them.  That was a big improvement in my book, and might be acceptable for many people.  However, I am a busy guy.  When the filters would run slow with the configuration, the culprit was the medium and coarse pads.  When I would pull them out, they felt like solid bricks.  I was amazed that these foam filter pads had become so hard and dense.  Cleaning them is a pain – running them under water, ringing them out, and repeat about 7 million times each, till the water runs clean through the pads.

My next target to “optimize” I am very good about performing weekly water changes, so even without the filter pads, I would still be pulling out the pollutants that would have been collecting on the pads.  I decided the pads would go, to be replaced by more Matrix media.  My final configuration looks like this:

I have found that my filters in this configuration can run in excess of 18 months without a material change in the flow rate.  If we negate the desire to “clean” the water of suspended solids using the filter, the primary purpose of the filter is to facilitate the beneficial bacteria feeding on ammonia and nitrites.  I believe my final configuration is superior in accomplishing that because of a few things:

1. The flow rate does not change over time, providing a more stable environment
2. Packing the filter with Matrix media provides huge amounts of area for bacteria to colonize in the filter
3. I can spend my time on more important matters, like making sure the tanks are well cleaned

I am interested in comments and criticisms on this approach.