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  • The front view of an Oase Filtral 5000 UVC underwater pond filter
  • The Oase Filtral 5000 UVC sitting on the bottom of a pond
  • The top view of an Oase Filtral 5000 UVC underwater pond filter
  • Internal structure and components: Oase Filtral 5000 UVC
  • The is the image logo for Oase


This is the image logo for Oase Filtral 5000 UVC

The Oase Filtral 5000 UVC Underwater Filter

The Oase Filtral 5000 UVC is an underwater filter pump that also includes a submersible Ultra Violet Clarifier. It is a multi-function unit, otherwise known as an all-in-one filter or a submersible pump filter. It is the larger brother of the Oase Filtral 2500 UVC.

What's inside the Oase Filtral 5000 UVC?

Inside the Filtral: sponges, UVC and biological media    Oase Filtral internals: Sponges, gravel and bio cores

The image on the above left is a cutaway section of the internals of the Oase Filtral 5000 UVC; the image on the right is a better look at exactly what is inside the underwater filter. Inside there are 2 different types of sponges, a blue coarse sponge and a black fine sponge which provide mechanical filtration; that is, they literally pull the physical particles that you can see floating around out of the water. There are 2 bags of pebbles and 8 'bio-cores' (those black spikey plastic objects) that provide surface area for bacteria to live on and clean the water biologically, facilitating biological filtration. The final element inside is the 2500 litre per hour (LPH) pump that draws the pond water through the filter and an 11 Watt ultraviolet clarifier which irradiates and kills algae. The fountain stem returns the water back to the pond via one of 3 fountain nozzles: the Vulkan, Lava or Magma fountain nozzles.

How the Oase Filtral 5000 UVC works

A Oase Filtral 5000 UVC on the pond floor

As you can see from the image above, the Oase Filtral 5000 UVC is placed in a level position on the floor of the pond. The electrical cable may be installed through the liner with an Oase Tradux, a special locking mechanism that allows the electrical cable to pass through the pond liner without cutting the cable and ensures that the pond remains water tight. The electrical cable does not need to be installed this way, it can simply run along the bottom and out the edge of the pond, however this is a great option if you want a tidy looking installation.

Water is sucked through the Oase Filtral 5000 UVC by a 2500 LPH pond pump. As the water passes through the outer casing it encounters the first element of mechanical filtration as the coarse blue filter sponge immediately removes the larger particles and decaying organic matter (fish poo, dead plants etc.) from the water stream. The water than encounters the second layer of mechanical filtration as the water stream passes through the fine black filter sponge where finer particles are removed before entering the bio-cores and filter pebbles. This is where biological filtration really kicks in, as the water is swished around through the bio cores and filter pebbles and hungry bacteria break down the organic waste cleaning and removing toxicity from the water. The final step inside the filter occurs when the water stream passes through the pump and then out through the 11 watt UVC, radiating the water with ultra violet radiation and killing any suspended algae in the water stream.

Finally, the freshly filtered water passes through the fountain stem and out of the fountain head where it delivers 2 final benefits. Oxygenation, as the falling fountain water hits the surface of the pond and adds precious dissolved oxygen back into the pond. And of course - beauty! You cannot help but be drawn in as the fountain gently ebbs the water into the air, and then the soothing sounds of water hitting water as it lands on the surface of the pond. Positively delightful!

You have a choice of 3 fountain nozzles

There are 3 different nozzle types that come with the Oase Filtral 5000 UVC: the Vulkan, Lava and Magma fountain nozzles.

Vulkan Fountain Nozzle

This is a fountain nozzle that comes as one of a set of 3 with the Oase Filtral 5000 UVC. It is a series of fine shots of water, not unlike a conventional shower head that shoots a shower of water up into the air.

This fountain nozzle is a series of fine shots of water, not unlike a conventional shower head that shoots a shower of water up into the air.

On an Oase Filtral 5000 UVC at full stream it will be 1m high and up to 1m in diametre.

Lava Fountain Nozzle

This Lava fountain nozzle is definitely the most popular out of the 3 included in the Oase Filtral 5000 UVC. It consists of a conical shaped fountain head the causes the water to fall like a mushroom shape, and looks like a bubble.

This fountain nozzle is definitely the most popular out of the 3 included in the Oase Filtral 5000 UVC. It consists of a conical shaped fountain head that causes the water to fall like a mushroom shape, and looks like a bubble.

On an Oase Filtral 5000 UVC at full stream it will be 30cm in diametre. Height is not a factor.

Magma Fountain Nozzle

The Magma fountain nozzle consists of 5 medium shots of water splaying out at an angle from the fountain head.

The Magma fountain nozzle consists of 5 medium shots of water splaying out at an angle from the fountain head.

On an Oase Filtral 5000 UVC at full stream it will be 1m in height and up to 1m in diametre. 

Cleaning and Maintenance

What you will need:

  • A clean, chemical free bucket
  • An old toothbrush
  • Replacement 11 watt UV tube (Once a year in September)

The Oase Filtral 5000 UVC underwater filter is easy to clean and maintain. If you have a pond with gravel and plants it should only need cleaning every 3 months, however depending on the design of your pond you may need to clean it more frequently. A good way to tell if your unit needs cleaning is to monitor the fountain flow rate. If it is slowly diminishing then its time to clean the filter.

Firstly, you will need to exercise some level of care in order to access the filter. Be sure you do not pull strongly on the power cord to drag the filter to the edge of the pond as this will put unnecessary strain on the electrical connection to the pump. Completely remove the unit from the pond to the edge of the pond and out of the water.

Take the clean bucket and fill it about half way with the pond water, and set it beside the underwater filter. This is where you will be cleaning the internal components, as we do not want to use tap water as the chlorine will wipe out our bacterial colony.

Next, unscrew the fountain stem from the main unit, being sure to remove the rubber seal at the base of the fountain stem before it falls off into the pond! Once the fountain stem is removed, un-clip the front and rear catches and remove the top cover. Here you will be greeted by the blue coarse sponge which will no doubt have done its job and be covered in muck. Remove the blue coarse sponge and then the black fine sponge and place it in the bucket that you just filled with pond water. Remove the bio-cores and the gravel bags and place these in the bucket also.

What you should have left is the base of the unit and the pump and UVC housed inside the base. Take your garden hose and clean the pump, UVC and outer casing with pressurised water. This will make sure all of the muck is removed without killing off the bacteria in your sponges, gravel and bio-cores.

You need to replace the UV tube every September. If you are replacing the UV tube remove the pump and UVC from the base of the unit. Next, hold the lever down and gently turn the UVC barrel counter-clockwise. Don't force anything, if it is not moving there is something blocking the movement which needs to be removed or adjusted. Once unscrewed, remove the UVC barrel and you should see a quartz sleeve covering the UV tube. Gently unthread the plastic nut at the base of the quartz sleeve, and then pull on the quartz sleeve to remove it from the transformer. You may need to pull with a bit of strength if you have not changed the UV tube for a while. Once the quartz sleeve is removed, remove the old UV tube and throw it away responsibly. The new 11 watt UV tube should be wrapped in bubble wrap inside the box. Taking care not to touch the new UV tube, hold the tube inside the bubble wrap and then insert the tube and fix it in the transformer. Again, this should go in fairly easily so don't force anything. Once the UV tube is secure, fix the quartz sleeve with the plastic o-ring and close up the UVC.

Now, take the bucket with the sponges and gently swish around and rinse the bio cores and gravel in the pond water contained in the bucket. These do not need to be absolutely clean, just wash off any muck and then place them in position back in the filter. Then take the sponges and squeeze them hard whilst holding them underwater in the bucket of pond water. What should happen is that as the squeezed sponges are released they then begin to absorb more water which you will squeeze again, ejecting as much muck as you can. Do this several times, you may need to empty your bucket of dirty pond water in the garden and collect another bucket or so of clean pond water and repeat the process if the sponges are really bad. Again, don't freak out if they are not super clean. Just make sure that most of the muddy muck has been ejected from the sponges and return them to their position in the filter.

Reassemble the filter by clipping the filter top back to the base of the unit. This can be tricky the first few times, especially when the outside of the unit is slippery from being underwater and collecting an algae film. You need to make sure that the pump and UVC are sitting correctly within the base of the unit, and take care with the power cord to make sure it sitting in the correct slot. You need to line up the threaded outlet where the fountain stem was unscrewed from and if everything is neatly inside clip it down until it locks. Don't stress if this takes a few attempts, it will go back together easily if everything is secure underneath.

Finally, the fountain stem can get pretty dirty and clogged as this is the outlet for the filter and dead algae tends to accumulate here after being killed off by the UVC. Take your old toothbrush and scrub of the rubbish until its clean. Seat the rubber seal around the threaded outlet and then reattach the fountain stem to the unit. Put the underwater filter back in the correct place and you should be good to go.

At this point, we like to add a few water treatments, like a good sludge consuming bacteria such as Pondzyme, a water clarifier and some Algaefix.

What is the ideal application for the Oase Filtral 5000 UVC?

The great thing about the Oase Filtral 5000 UVC is that it is such a handy, all-in-one solution for small ponds. Almost invisible, it eliminates the need for hoses running to and fro and the inclusion of an ultra violet clarfier makes it a tough one to beat when it comes to filtering small ponds. Every customer of ours that has brought this unit has absolutely loved it and testified to the effectiveness of this filter. The added benefit of a built in UVC keeps green water away and the simple pop off lid makes cleaning a breeze.

In our experience the Oase Filtral 5000 UVC is perfect for small ponds and water features up to 2500L that have a low biological load; that is, not a lot of large fish. An important factor to keep in mind is the depth of the pond that you are planning on installing the underwater filter into. If the pond is less than 20cm deep you could have some problems as the all-in-one filter will be sucking water from the surface and sucking in air and water which will inhibit the filtering capacity and ultimately put unneccessary wear on the pump. Ideally you want to install the filter in a pond that is 30cm or more deep.

In a small pond or water feature with small pond fish they will perform perfectly, but don't expect to filter a koi pond with this unit. For that you need to be looking at something more substancial like an Oase Filtoclear unit.

Although the pump is a 2500LPH pump, the flow rate is reduced to 1100LPH once it passes through the filter and reduces even further over time as the filter sponges capture the sediment so keep this in mind if you are looking to run a small water feature from this unit instead of the fountain head.

The 11 Watt UVC does a great job of keeping water clear in small ponds. Remember, that a UV tube is only good for 6 months as after that the level of radiation emitted from the UV tube decreases to an ineffective level. Make sure you replace the UV bulb every September to get the best of use of the UV over the warmer months. You can buy UV tubes in our store here.

How much does it cost in electricity to run the Oase Filtral 5000 UVC?

There are 2 energy components that contribute to what the running cost is in terms of energy consumption: the 35 watt pump and the 11 watt UV tube. The total wattage of the unit is 46 watts. If you run the unit 24/7/365 (which all filters should) then the energy costs are calculated based on the average Kilowatt per hour (KWh) costs that you can find on your bill. In NSW at the time of writing this it's about an average of $0.32 per KWh, which breaks down as the following:

  • $0.35 per day
  • $32.24 per quarter
  • $128.95 per year

There is a great running cost calculator available here at the Clearpond Website

Frequently Asked Questions

Q. How noisy is the Oase Filtral 5000 UVC underwater filter?

A. The sound emitted from the Oase Filtral 5000 UVC is minimal. Not only are they engineered to run super quiet but they are also underwater so the noise emitted from them is not going to be noticable. Given the fact that there is a fountain stem directly above the filter means all you will hear is the beautiful sound of falling water.

Q. How easy is it to clean the Oase Filtral 5000 UVC underwater filter?

A. Of all of the all-in-one filters on the market we believe that the Oase Filtrals are the easiest to clean and maintain.

Q. Can I modify the electrical cord to hard wire into the mains power or remove excess length from the cord?

A. The electrical cord can be modified and as long as it is cut more than 60cm from the unit it will still be covered by warranty. It is recommended that a licensed electrical contractor performs the modification. Remember to allow enough cord to be able to access the filter by completely removing it from the pond.

Q. My pond is filthy green. Can I buy the Oase Filtral 5000 UVC and throw it in straight away to solve all of my problems?

A. A green pond is generally a filthy pond and adding a new filter to a filthy pond is only going to rapidly clog the filter. It's always best to either completely clean the pond first, and then install the new filter. At the very least, you should complete a large water change to start with fresh clean water.

Manufacturers Resources

Product Video

Technical Data

Dimensions (mm) L x W x H 380 x 290 x 160mm
Power Consumption (watt) 35
Turnover rate max. (l/h) 1100
Head of water max.(m) 2.3
Connection Cable (m) 10
Guarantee (excl. wearing parts) 2
Operating Cost 82.66
Dry Installable N

Downloadable Manual:


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Warranty Information

The Oase Filtral 5000 UVC has a 2 year guarantee covered by the distributor. This 2 year guarantee covers the pump motor only and not the pump impeller.
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1 Review

  • 5
    This underwater filter rocks!

    Posted by Brad on 31st Mar 2017

    This underwater filter is amazing! Gone are the days of green water, the filter removes any floating debris and the fountain provides the tranquil sight and sound of falling water. It is also pretty much invisible when its running too, so no messy pipes running around the pond. I have this filter in my small fish pond out the front and would recommend it to anyone who has a small pond or water feature.

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