What is Floating Raft Aquaponics?

A successful aquaponics system requires a mixture of fish, plants, pumps, and testing to ensure all the elements remain in harmony.

But one factor that is often overlooked is the use of filters to improve the efficiency and reliability of your system.

The floating raft is widely regarded as one of the best systems you can utilize to remove hard waste and excess fish food. This prevents your pipes from getting blocked and allows the plants to absorb nutrients; allowing them to mature into strong and healthy plants.

If you’re growing crops to consume then you’ll appreciate the power of a good filter.

What Is A Raft Filter?

The basic principle of your raft filter is to remove the solid waste particles and house the bacteria.

The filter consists of three chambers where the water overflows into the next chamber. The particles sink to the bottom and the compartmental divides absorb any stray bits; allowing the water to move around the system without clogging the pipes.

raft filter for aquaponics

When the clean water goes to the plant beds you can also implement a floating raft system. The main difference with this is that it is not looking to collect debris. Instead, it provides a surface to grow your crop which flats on the water; allowing the plants to dip their roots in the water and get as much water and nutrients as they need.

Your Choice Of Material

There are several options regarding the Material used in your floating raft system:

  • Polystyrene Sheets

These are cheap to buy and surprisingly effective in your floating raft system. You can purchase huge sheets of these and cut them to fit the size of your tank or tanks.

This is a good choice as the cost is minimal and the holes can be easily made or enlarged to accommodate your plants.

floating raft aquaponics

What is also great about this system is that you can select a tank large enough to have several different stages of plant alive at the same time. The boards float and will gradually move on the water. By planting seedlings you’ll be able to add more seedlings after they have moved and created a space big enough for the next batch of seedlings.

The plants will gradually float across the raft; becoming fully grown by the time they reach the other end. This allows you to pick them out and then plant new; effectively creating a never-ending cycle.

This is actually the option that many commercial aquaponic set-ups use.

  • Foam

This is another option for your floating raft tank. It is not as effective at floating as the polystyrene sheets. Unfortunately, the foam will not last for as long as the polystyrene; adding to your costs. In many cases, the foam is only good for one season.

  • Plastic

Another option, although not one that is used often, is plastic sheets or guttering pipe. This can have holes drilled into it for the roots to dangle in the water.

Plastic will last for a long time but you may have issues with stability and this can be a more costly solution to the material issue.

  • Home Made

In order to keep your costs low, you may wish to consider adding some plywood to plastic or even pieces of foam that you have lying around. Providing the material floats it can be put on the water and used to accommodate your aquaponics plants.

However, you need to consider whether the material is likely to rot in the water or not. If it does then you’ll need new material every year which can be time-consuming and expensive. This makes it a good option for when you are experimenting with aquaponics but not a worthwhile long term solution.

It is also worth considering what wood you are using. Plywood is glued with glue which contains formaldehyde; it is likely to stunt the growth of your plants and fish; it could even kill them.

  • Organic Styrofoam

If you are concerned about your environmental footprint you may like to purchase organic Styrofoam boards. These work in the same way as the polystyrene boards but are certified to be environmentally friendly.

It is even possible to paint these boards although you’ll then need to face the discussion regarding environmentally friendly paint and whether darker colors are better or not.

White is said to attract more algae which is not good for your system. However, many people consider white as a better color for seeing the algae and maintain that it is not responsible for increased algae production.

The Right Aquaponics Floating Raft Material

The bottom line is that the material you use will depend on what type of setup you have, your current budget and your level of experience.

It is fair to say that polystyrene boards are the cheapest and easiest option in most instances. However, if you are concerned about the environment you may wish to choose organic Styrofoam and if you are simply experimenting with the possibility of aquaponics anything that floats can work.

But don’t forget that you need to consider the effect that your float material may have on your setup; it could introduce undesirable toxins. The same is true for any paint you decide to add to your float; make sure it will not have a detrimental effect on your set-up!

It is also essential to remember that a good raft will float freely inside your trough. Don’t be tempted to narrow the trough in order for the raft to fit snugly and eliminate the potential for algae to form. It may work in this respect but it will not allow the plant to move through the tank as it grows; creating the never-ending cycle. Instead, you’ll have to keep moving it.

The bottom line is that it is best to invest in some polystyrene sheets and test out your aquaponics setup; you can always upgrade your raft material later if required.

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