The Filter Myth

     Most people are under the impression that filters actually clean the water. And while they do remove large particles and trap them in a sponge or similar device, all this really does is concentrate the debris in one area where a bacterial colony can easily access it. What the colony can't take care of can simply be rinsed away weekly or monthly. Perhaps even yearly depending on the filter and the bio load. Unfortunately, i have never found a filter i liked or was confident in their effectiveness. Hob filters always seemed to clog up quickly and canisters always seemed way too over priced. Under gravel filters while i liked them, i liked the look of sand better.
     I discovered matten filters at some point and i thought they were good but unattractive. Also the material seemed always out of budget. In one article i read where folks were strapping moss and other plants to the matten filter masking it and i thought this was a great idea, if only the material wasn't so pricey.

Look Closely at the right side. You can make out the uplift tube of my sponge filter.

    What I'm running now and am incredibly happy with are sponge filters. I use over powered air pumps to run them. My 45(actually water 20gal) and my 55(actual water 30gal) have two sponge filters each, run off of an air pump rated for 100gallons. These are planted tanks that are not co2 injected but i due dose excel and they covered with glass so i believe co2 levels build up under the glass and the pumps find a balance. Which is more important then increased co2 levels in my case. I believe the plants can deal with low levels of co2 if it is stable. I do weekly water changes of 5 gallons on each tank. I strapped anubias frazeri and barteri to the filters and they quickly rooted into them. Faster then i have ever seen these plants root. I also have tied    red myrio and other stem plants to the sponges with success.
     In the environment that i created i believe the plants on the sponges due well because nutrients of all types are constantly brought to the plant's roots allowing the plants to divert resources to light gathering or co2 gathering. Root disturbance happens twice a year when i give the sponges a through cleaning with a garden hose and a couple of squeezes. I use the hose because it takes only a few moments versus squeezing with tank water that can take forever with fairly poor results.

Let's play find the sponge in this one.

     In smaller tanks of ten gallons or less i don't even use sponge filters. I believe water movement is more important then actual "filtration".I use a 30 gallon air pump to run an air stone in a ten, a sponge filter on a five and three air stones in three different 2gallon containers. I'm using the five gallon to rear some fry and it's a wee bit over crowded. The ten gallon is so thickly planted that 10 ottos, a pair of drape fin barbs, their fry and lonely male betta can all hide to the point of invisible.The 2 gallon containers are the winter homes of my paradise fish and paleatus cories. also thickly planted.

This ten gallon is runs just an air stone for water movement.

     I truly believe water movement is vital in an aquarium environment. I also believe plants are the best nutrient exporters around and should be in every set up. In the average, moderately planted tank this should all work. In an over stocked or impossible to plant tank then a hob or canister filter is necessary, if only to add additional space for bacteria colonies. The water Change volume also has to change. Where as plants will use up the final stage of the nitrogen cycle or even use ammonia directly your filter will not. Slowly this will build up and your fish will be just as dead.
    Terrestrial plants grown hydroponically in the system will lead to complete nutrient exportation, i.e . the plants with sequester the nutrients in their leafs outside the aquarium versus aquatic plants that sequester the nutrients in the aquarium. If the leaves die on aquatic plants they stay in the aquarium releasing the nutrients back into the water, with hyrdoponic plants the leaves fall to the floor and outside the aquarium.