How to make a filter for small fish tanks

How to make a filter for small fish tanks

Updated on 2/10/15, Originally posted on 9/17/11

Bible Verse: Genesis 1:20 Then God said, “Let the waters abound with an abundance of living creatures . . .

God created fish on the 6th day of creation.

Fish need a filter to keep the tank clean, and also an air pump so your fish will not run out of oxygen in the water.  Did you know that you can use an air pump to make a fitter?  When you are finished fallowing these instructions your air pump will double as a filter!  This will save you money because you won’t need to buy a filter too.

Sample tank with an air pump being used as a filter.

Using an air pump as a filter will work best for small tanks that are no bigger than 4 gallons.  Tanks bigger then this will need a filter designed for that size tank.

To get started buy a big cheap yellow car sponge and suction cups that have plastic hooks on them (avoid suction cups with metal hooks as metal can be harmful to fish).  Using a knife, cut the sponge into several squares (now you will have several replacement filters for later).  Using scissors poke/twist a small hole in the top of a sponge and go about half way down into the sponge.  You want the hole to go to the center of the sponge and then stop.  Now place the air tube in the hole of the sponge.  Take the suction cup with the hook, and place it on the inside tank wall near the bottom floor.  The air tube, that now has the sponge attached to it, needs to be hooked on the suction cup to hold the sponge under water.  You want the sponge to be completely submerged and if possible you want the tube to make a “J” with the sponge on the end of the “J”.  If the sponge comes off the tube you made the hole too big and you will need a new sponge to try again.  The suction cup with a hook should keep the sponge and tube from floating up.

How it works: The air that goes through the sponge and out the top will draw dirt and debris into the sponge.  As time goes on the sponge will become dirty and need to be changed; about every 1-3 weeks depending on how many fish are in the tank.  Go ahead now and give it a try!

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