A cheap, quick, and easy micro filter for your fish tank. These can be customized to your needs. It works by allowing air to push/pull water through the filter.
Step 1: Parts
1. A pill bottle with the label removed (clean the bottle well! We don't want to poison the fish. I boiled my bottles)
2. a large screw, a small screw, and screwdriver (a drill is better but I improvised)
3. any type of filter media (I used ceramic rings to increase my biofilter)
4. air pump, air line, and air stone (on fish tank)
Step 2: Step 1: Decide Whether You Want to Put the Airstone in the Bottle or Outside the Bottle
There are pros and cons to both. Airstone in the pill bottle creates more suction but decreases the surface area available for filter medium. I found the bubbles coming from the outlet holes were much larger as well which might scare/hurt fish.
Airstone on the outside of the pill bottle creates smaller bubbles but the suction into the bottle is not as intense. An advantage to this method is that there is more volume in the bottle for filter mediums. I used this method on my first bottle for the biofilter as surface area is important.
Step 3: Step 2: Drill Your Holes Into Your Pill Bottle
Decide which side of the bottle is top and which is bottom. I used a screw and screw driver to burrow into the plastic. A drill would work too...Drill holes for your inlet and outlet. Inlet holes go on the bottom side of the bottle; outlet holes go on the top side of the bottle. My inlet holes were slightly larger than my outlet holes. larger inlet holes allows more water in and prevents clogs. Smaller outlet holes make the air bubbles smaller. experiment and see what works for you. The air hose hole is just large enough the the air hose. for the airstone in method, you only need a large hole on the top of the bottle. For airstone out method, you need a hole on the top and the bottom of the bottle to thread the air tube completely through the bottle.
Step 4: Hard Part Done; Lets Get Creative
now that you have the skeleton of the filter, it's time to put the filter together. First, thread the tubing and place the airstone either in the bottle or just underneath the bottle. Now fill your bottle with the desired filter medium. Get creative. Add activated charcoal, sponge, biomedium. If you don't fill the bottle full of biomedium, you can even have a moving bed filter. Now close up the bottle and install the filter into the aquarium.
Step 5: Additional Ideas
some medication bottles can be pushed into each other to create a stack...you can make a bigger filter with these.
-rough up the inside of the bottle with sandpaper to create an ideal surface for bacteria attachment.