Under Gravel Filters never wear out (unless Eric gravel vacuums them).  

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Ramming your gravel vacuum cleaner too hard fractures your filter.

However, power filters take much less time to maintain – simply change the cartridge.  (Alright, you need to take the impellor out and clean out the slime monthly.)  U.G. and power filters both provide the three forms of filtration:

1.  Mechanical – takes out the lumps,

2. Chemical – takes out colors and smells,

3. Biological – converts nitrogenous wastes.

Power Filters consist of a water pump that pulls water up and out of your tank and into a box that hangs on your tank’s lip.  Gravity pulls the water back into your tank.  Your water passes thru various filter media as it returns.  This turns your tank over several times per hour and provides a water current your fishes love.  As the water cascades back into your tank, it circulates your tank’s water so it all eventually goes thru your filter media.

Filter Media usually consists of a cartridge – a porous “bag” containing carbon.  The bag filters mechanically. The porous cartridge itself strains out lumps that would cloud your water, feed excessive bacteria, and reduce the oxygen content of the water. 

You can also add different filter media to the cartridge to increase its effectiveness.  The carbons and resins filter chemically.  Carbon in the bag adsorbs colors and smells.  It “polishes” the water.  Zeolite in the cartridge adsorbs ammonia.  You can also add nitrate and phosphate adsorbers that starve algae.

Eventually, waste-removing bacteria also grow on the porous cartridge – and especially on the “bio-wheels” or sponges or other bacteria-growing materials.  These bacteria filter biologically.  The nitrosomonas and nitrobacters change otherwise harmful ammonia and nitrites into harmless substances.

Dirty bags clog up and eventually the water flows around them and back into your tank thru a small shunt.  It is now time to change your cartridge.

Save a $?  Some thrifty souls take their dirty cartridge over to the sink and wash out the dirt that clogged the pores.  This saves a little cash but eliminates the minimum maintenance feature of these very effective filters.  Unfortunately, it also reduces their effectiveness.  By the time the cartridges clog, their carbon and resins are more than used up.  The cartridges also clog up again very quickly.

Medications.  If treating for any type of disease, make sure you remove the carbons and resins.  They will adsorb, absorb, or remove any medication you use.  

Aeration.  Some people worry about “lack of aeration” with these filters.  Not to worry.  Aeration takes place at the water’s surface – not from the tiny bubbles coming up your air stems.  Your power filter aerates your tank as it filters it – even if your cartridge becomes totally clogged with debris.

One brand of power filter contains a protein skimmer that removes nitrogenous waste products mechanically.  An aerator causes the waste products to “foam up” into a removable cup.  Salt water enthusiasts use these because nitrogenous waste products are much more poisonous in saltwater (the higher pH).  Also, water changes cost much more when changing saltwater.

You can increase the effectiveness of your power filter by using any of the one-drop-per-gallon flocculants.  These products cause small particles (usually bacteria and infusoria) to lump together into larger particles.  Your filter then removes them faster.

Other power filter tips that will make your life easier include:

1.       Never overfeed (because the extra bio-load can exceed your filter’s capabilities).

2.       Put a strainer on your uptake tube (to keep debris and fish out of your impeller).  Once a fish runs thru one of these piscatorial salad shooters, it rarely survives.  

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Crud like this will reduce your filter flow by 90%.

3.       Wipe out your impeller housing once a month (because debris happens).

4.       Maintain your regular weekly water changes (to maintain water quality and stability).

5.       Change your cartridge every four to eight weeks (because you use up the carbon).

6.       Cut off a strip of your old cartridge and drop it in your filter box (to maintain optimum bacteria-based biological filtration).  

Diatoms Make Super Filters.  Like the other power filters, the diatom filters move tremendous quantities of water – 300 gallons per hour.  But diatoms work quite differently.

Tiny algae cells that lived in the ocean extract silica from the water and used it to build a protective cell wall.  These diatoms live in the ocean in countless quantities.  When they die, their shells settle to the bottom and form diatomite – diatomaceous earth or diatom powder.

Diatomite consist of dust-fine white shells with countless protruding spines and projections.  Only very fine particles can get past a layer of diatoms.  They literally screen out anything down to one micron in size (one thousandth of a millimeter).  This means they filter out many disease organisms – including ich.

Diatom filters work by coating a nylon bag or fiber core with a layer of these sticky shells.  Then they force the water through the layer at high speed.  This removes virtually all visible particles.  Diatom Filters make a 10 gallon tank crystal clear in 10 or 15 minutes, no matter how dirty it was to begin with.

Many people make the mistake of cleaning their gravel with their diatom filter.  What a waste.  You can take 98% of that crud out with a cheap gravel vacuum cleaner at a fraction of the cost.  Your diatom filter will clean 10 tanks without recharging unless you use it to clean your gravel.

With powdered carbon, you can take out colors, odors, medications, and fish wastes.  With the proper resins, you can remove nitrites and ammonia – almost instantly.

You need to clean your diatom filter when the flow slows.  Rinse off and replace your diatom powder.    Dirt on the bag/core cuts your flow rate by 50 per cent or more.  This won’t hurt the filter, it just makes it take longer to do the job.

If you recharge your diatom and the flow stays slow, you need to clean or replace your bag or filter core.  Fish slime, dirt, and bacteria eventually clog it.  

Combination.  Using both under gravel and power filters together gives you excellent filtration – the best of both worlds.  LA.

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