This siphon is designed for mini/desktop aquariums and fish tanks, such as betta tanks or those holdling 5 gallons or less. Cleanliness is very important for fish tanks, but siphons used for larger aquaria tend to be unweildy for smaller ones. Bigger siphons also have hoses of larger bore, which can decimate plants or accidentally suck up small fish.

An additional feature with this siphon is that you will not be directly sucking up aquarium water.

Step 1: What You'll Need:

Airline tubing - the small diameter makes it safe for small fish, and is easy to maneuver in small tanks; length depends on your aquarium set up. Mine is about a meter long.

Stiff plastic straw - this will allow you to move the siphon in the tank without putting your hand inside. This means the fish will be less disturbed when you clean the tank.

Clean, food-safe airtight plastic container - it should be big enough to hold the water you will be removing from the tank, but not too big because that would make it hard to establish the vacuum to start the siphon. You can use glass, but it would be heavier. I am using a large popcorn tub.

Blu-tack - used to seal holes and make things airtight

Scissors

Step 2: Schematic

How it works:
You put the inlet tube in the fish tank, the suck on the mouthpiece. This decreases the air pressure in the container, which will draw the water in. Because of the container, there is no direct connection between your mouth and the tank, and you will not end up accidentally swallowing aquarium water.

Step 3: Cutting the Tubing

Cut the airline tubing into two lengths, a longer one (1 meter in this case) and a shorter one. The shorter tubing is for your mouth.

Step 4: Inlet Assembly

Feed the end of the straw into the longer tubing. It should be a snug fit. Be careful not to crush the straw.

On the other end of the straw, you can put a smaller piece cut at an angle. This will make siphoning detritus from crevices and corners easier

Step 5: Preparing the Lid

Get the lid of your food container and carefully cut two small holes opposite each other. Try to make these holes as neat as you can. The tubing will go in these holes.

Step 6: Lid Assembly

Thread the tubing into the holes. About 2-3cm should do it (an inch or so.)

Step 7: Sealing the Lid

Use blu-tak to seal the tubing into the holes and make it air tight. Do not compress the tubes.

Step 8: Completed Siphon

Put the lid on to the container. The siphon is now complete.

Step 9: Using the Siphon

Put the straw end (inlet) into the aquarium
Suck on the mouthpiece, this will cause the air pressure in the container to drop and draw water from the tank in.
Vacuum your aquarium with the straw, moving it around to get all the dirt and detritus.

Important Note: you must keep the container lower than your fish tank at all times. This will allow air pressure and gravity to keep the siphon going

Tip: water from fish tanks is great for plants

Introduction: Siphon for Mini Aquariums