DIY Charcoal Bag Aquarium

Place a sheet of newspaper on a table. Stand the water bottle on the newspaper. Measure up 4 inches from the bottom. Cut through the bottle as you turn it clockwise with the blade of a utility knife. Break off the bottom from the bottle once it has been cut through.

Place the cut bottom face down on the newspaper. Cut a hole through the center with the utility knife. Place the water bottle cap on the table face up. Cut a hole through the center of the cap with the utility knife. Screw the cap onto the water bottle. Stand the water bottle on the newspaper with the cap end down.

Fill a paper cup halfway with aquarium gravel. Pour the gravel into the open end of the water bottle that is standing on the newspaper.

Measure one-inch marks along the length of the straw. Cut the straw at the one-inch marks with a scissors. Insert an end of each of the cut straw lengths into the gravel. Push the filter mesh into the open end of the bottle until it is all the way inside.

Cut a hole in the closed end of the flower pod with the utility knife. Hold the pod with the wide open mouth facing up. Push the free end of the airline hose that is connected to the aquarium pump halfway into the pod.

Insert charcoal granules into the pod. Continue to insert charcoal granules into the pod until it is filled to the top. Press your fingers against the granules to compress them at the top.

Push the end of the pod where you made the hole into the hole in the plastic bottle bottom. Run a line of bonding glue around the pod where it meets the hole. Let the glue set overnight. Place the bottom on the bottle that is standing on the newspaper.

Wrap strips of silicone sealant tape around the seams between the bottom and the bottle. Run a line of silicone sealant paste over the tape. Run a line of the silicone sealant paste around the end of the pod where it meets the hole of the bottom.