Bathtub Aquaponics

One of the great things about Aquaponics is how you can use recyclable materials to make an inexpensive system for your backyard. Murray Hallam built a very cheap system using two old bathtubs stacked on top of each other.

Here in Australia you can purchase a used bathtub from the rubbish tip for around $10. Your main expense is to buy a submersible pond pump. Prices can vary from $80 to $300 for the more durable European designed pumps.

We have used the cheaper Chinese made pumps with good results.

Click on the Red Button on the animation to stop and start the animation of the Bathtub Aquaponics system. Easy isn’t it?

The basic plan is two use the top bathtub to act as your vegetable grow bed and the bottom bathtub to be your fish tank. Murray recommends that you source the following products to complete your kit.

– Two bath tubs ($20)

– Six besser bricks (concrete blocks) to support your growbed tank ($30)

– A quantity of recycled timber or plywood to make a cover for the fish tank.

– Sikaflex in caulking gun to plug tank connections

– Spirit Level (Water is heavy and a perfect level to site your system is advisable)

– Shovel (Handy for leveling out your ground)

– Mattock or Crowbar if your ground is hard

– Growing Medium ( Canna clay pebbles or 20 mm Gravel ) Make sure you choose pH neutral gravel free of calcium

– Seedlings

– Water

– Fish (Buy a dozen small goldfish)

– Wedges to prop up your fish tanks and keep them level

– House brick (useful to keep your siphon steady when you fill up your Growbed with 20mm gravel)

You will require to build a siphon to flood and drain your bathtub aquaponics system. The purpose of the siphon is to draw oxygen to the roots of your plants. Plant roots that are continually submerged in water will rot if they don’t get enough oxygen. You can leave plants roots submerged in water continually if it is heavily oxygenated.

You can add an additional aerator to your system if you plan to use fish that require heavily oxygenated water. For the bathtub system goldfish could be used to act as your plant nutrient suppliers. Murray recommends no more than 10 larger fish if you intend to grow them out to eat.

A word of caution about Bathtub systems is that they are probably as small a system as you should attempt to make. The volume of water is a bit on the low side at around 250 liters. Larger system of 1000 liters are preferable but more expensive as suitable containers are harder to source. They are really designed as a beginners first attempt.

Do not use pea gravel or sand in your grow bed as this will clog your system and fail to work properly. Use 20mm or three quarter inch gravel. This can sourced from any landscape building company. For a small family wishing to have their own supply of lettuce or herbs, this bathtub aquaponics system works very well.



Building a system like this is an ideal weekend project for the handyman or woman familiar with plumbing materials from various hardware stores. If you don’t wish to experiment at making your own siphon and want to buy all the fittings ready-made, you can do so by ordering the bathtub kit directly from Murray Hallam. This kits comes with all the fittings you will need including the right pump to power your system. You will need to supply your own bathtubs and select you own fish and plant seedlings!

If you are new to Aquaponics and want to know more about cycling the system, how to measure the correct pH and make sure that the water parameters are all perfect for you, why not order Murray’s popular Aquaponics Made Easy DVD.

At over 90 minutes long, it goes into a lot more detail than mentioned on a blog.

It’s had rave reviews from many experienced Aquaponics users and features a great segment on Murray Hallam showing you in detail how a bathtub aquaponics system works. There’s even a detailed section on the DVD showing Murray assembling from scratch a larger kit and explains the whole process of growing different fish based on your climatic conditions. What fish work best for your location? What plants can you grow? It all on this great DVD. Together with his Secrets DVD they make a terrific collection for the home hobbyist and experienced aquaponics user wishing to learn more about this fascinating topic.