How To Make A Fish Tank Filter (3 Easy Methods!)

How To Make A Fish Tank Filter

Filters are necessary if you want to keep your tank clean, and your fish happy and healthy.

However, they can be some of the most difficult things to buy.

Not only can they be expensive, but there are so many different kinds.

It can be difficult to know what will be best for your tank – and the right filter can make all the difference!

However, we have a solution! Making your own filter is not too difficult.

If done correctly, it can be a cost-effective way to keep your tank clean.

We will show you how to make three different filters, all best suited to different types of tanks.

Method 1: DIY Bottle Filter

These are most suitable for larger tanks.

You Will Need

  • A bottle
  • Power head
  • Airline tubing
  • String

Pick A Water Bottle And Power Head

The powerhead you choose to use should pump double the water into your fish tank per hour.

The bottle’s neck should fit over the intake valve on the powerhead.

Cut A Hole Into The Bottle

You’ll want to cut two-thirds of the bottom of the bottle.

Pick a bottom corner to cut, leaving the base in place. This is so the filter material also stays in place.

Fill The Bottle With Filter Floss

You can buy filter floss at the majority of pet stores.

Put the floss into the bottle so it is dense, and it should catch the debris.

Add 2 Inches Of Filter Media

You can use activated charcoal or any filter material you’d like.

This will help to remove bacteria and toxins.

Add More Filter Floss

Remember to pack it together well, so it can filter out big pieces of detritus.

Wrap The Bottom Of Your Filter In Mesh Material

This is only necessary if you have specific types of fish.

Namely, small fish, delicate fish, or shrimp.

Make sure the mesh is fine, and then wrap it over the hole.

Secure it with string, or something similar.

Place The Power Head Intake Valve Into The Bottle

Take the power heads’ intake valve and place it into the mouth of the bottle.

This will get rid of all the dirty water by sucking it into the bottle.

The filter materials inside the bottle will clear the dirt.

Fit Airline Tubing Onto Power Head

Take 3 inches of airline tubing and fit it onto the output nozzle of the power head.

This is what the clean water will come out of.

Place The Bottle Filter In The Tank

Make sure the airline tube is pointed towards the water’s surface.

DIY Aquarium Filter

Method 2: DIY Sponge Filter

Sponge filters are better for delicate tanks.

You will need

  • Power head (ideally one that can pump twice as much water per hour as the water in the tank)
  • Aquarium sponge
  • Plastic tube
  • Airline tube
  • Styrofoam/PVC end cap
  • Electric drill/heated nail + hammer
  • Ruler/measuring tape

Put The Plastic Tube On The Power Head’s Intake Valve

Ideally, the tube should be twice the height of the sponge.

Cut The Sponge So It Fits The Tank

Make sure you are using an aquarium filter sponge that is wider than the plastic tube.

The ideal sponge has large pores which houses good bacteria effectively.

You can find them at the majority of pet stores.

Measure The Height Of The Sponge

Once you have done this, mark the height on the plastic tube.

Below the mark, make some air holes in the tube.

You can choose between an electric drill or a heated nail and hammer to make the holes.

You will need to make 8-10 holes per one inch of the plastic tube.

Plug The Tube

Even though the tube is going into the sponge, the bottom needs to be plugged up.

To do this, you can use styrofoam or a PVC end cap, provided it fits the tube.

Then poke a hole in the sponge, and slide the tube in.

You can use your finger to poke the hole.

Once this is complete, push the tube to the bottom of the sponge, so that the sponge covers all of the holes.

Attach The Plastic Tube To Your Power Head’s Intake Valve

From here, the power head can suck up the water, allowing it to go through the sponge.

This means all the dirt and mess in the tank will get caught in the sponge.

Then cut some airline tubing and plug it into the air pump (outtake valve).

Around 3-4 inches of airline tubing will work best.

Clean water will flow from this tube back into the tank.

Now you can place your new filter into the tank.

Make sure you place the output tube so the water comes out close to the surface.

DIY Sponge Filter

Method 3: DIY Capsule Filter

This filter is perfect for small tanks.

You Will Need

  • Small, cylindrical capsule (film canister, empty fish food container, or a prescription container)
  • Plastic tube
  • Airline tubing
  • Electric drill/heated nail + hammer

Clean The Capsule Using Hot Water Only

Ensure you do not use any chemicals or soap.

This may harm/kill your fish.

Film canisters can sometimes contain traces of heavy metals.

In this instance, they will need to be cleaned out with a tap water conditioner as well as hot water.

Note: The appropriate conditioner will say it removes heavy metals.

Preparing The Tube

Take the end of the plastic tube and cut a notch into it.

Plastic tubes can be found at the majority of pet stores.

The tube should be half an inch wide, and you’ll need to cut it down to six inches long.

You can choose between cutting a notch into the bottom of the tube, or cutting the bottom at an angle.

Cut A Hole Into The Capsule’s Lid

This hole must be smaller than the hole in the tube, but you can cut it in either the middle or edge of the capsule lid.

This will create a snug fit once the tube is put in.

Then put the capsule’s lid on and slide the tube all the way down.

The angled side of the tube should hit the bottom of the capsule.

If you chose to cut a hole close to the edge of the lid, the angled side of the tube should also face the center of the capsule.

Drill Holes Into The Capsule Lid And The Tube

Using an electric drill or a heated nail and hammer, poke some holes in the capsule lid.

Poke small holes in the flat area left around the tube.

Drill a hole into the side of the tube. The hole should be small.

While still keeping the tube inside the capsule, measure half an inch up from where the tube meets the lid (the seam).

Mark it, and then make the small hole using your electric drill or heated nail and hammer.

The airline tubing should fit snugly through this hole – so make sure it is slightly smaller.

Put The Airline Tubing Into The Hole

Put the airline tubing into the hole, making sure you feed it down the bigger tube.

Do this until it is halfway down the capsule.

Then lift the lid. While lifting the lid, make sure the plastic tube stays in place.

If you do not, the filter media will get stuck underneath it.

Put The Filter Media Into The Capsule

You can use any media, such as activated charcoal or zeolite.

You can find these in the majority of pet stores. Once you’ve done this, put the lid back on tightly.

Finish Up

Put the capsule at the bottom of the tank.

Ensure the capsule and plastic tube are under the water, while the airline tubing should be outside of the water.

Attach the end of the airline tubing to the air pump.

Measure the airline tubing to see if it needs to be cut down, and cut if needed.

Once at the correct length, you can plug it into the air pump. Now, your filter is ready to use!


So there you have it!

Three different filters that can be made with ease by following the instructions.

If made correctly, your tank should stay clean, and your fish will be happy.

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