Ozone Systems for your Koi Pond
At Koi Water Garden, we are able to offer competitive prices on not only high quality koi, but also on koi related goods including ozone systems to provide the ultimate in water quality.
last updated 23rd September 2024
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All about Ozone in Koi Ponds
We are the UKs premier supplier of ozone systems for Koi ponds and aquatic applications and are delighted to be able to offer a full range of Ozone systems and components which can be tailor made to meet your requirements - From Quarantine systems of 500 gallons to mega ponds of 100,000 gallons plus. Koi Water Garden Ltd now offers a complete and tailor made range of ozone equipment for Koi ponds and aquatic applications which are designed and manufactured in the UK . We are also distributors for the world famous Sander systems from Germany, but the really good news is that a working system can now be yours for under £500! But the good news does not stop there! We can now offer either complete systems or individual components which allow the user to tailor any system to exact requirements and ALL units can be serviced by us. We also offer an installation service if required and advice about which is the best system for you and how to install it.
KoiOzone Ozone generators
The KoiOzone range of ozone generators first introduced in 2011 are exclusive to Koi Water Garden Ltd and are manufactured by us in the UK. This is the first time that ANY European manufacturer has been able to offer a full range of ozone generators and complete systems which have been especially developed with Aquatics in mind to cater from the smallest, to the largest system. Our latest models, have been redesigned to take advantage of the latest Titanium and quartz ozone cells coupled to intelligent digital controllers. This latest technology means that the new systems are smaller, use less power, but are substantially more powerful then the units they replace. Perhaps most significantly though the new technology means that the new range cost up to 40% less than the original models. Spares and service costs are also significantly less expensive. These are robust and reliable corona discharge units and unlike most other commercially available ozone generators are easily serviceable by ourselves and are easily maintained. This is vitally important for all corona discharge technology used by most ozone generators, as units do need servicing from time to time. Our units are specifically designed for use in DRY ambient air or oxygen, and have rugged cell designs to resist the effects of moisture ingress. Now all models can be coupled to standalone Oxygen generators to effectively double the power output and increase efficiency and service intervals. All of the units featured below can be fully automated by incorporating Redox monitor/controllers (see below). They represent fantastic value for money in terms of price/performance compared to just about any other manufacturers product range.
Please note that the suitability of systems for pond sizes recommended below depends on stocking densities, organic load on the pond as well as other factors, including the Ozone reactor/Protein skimmer chosen. Larger systems are available and built to order for ponds and water features up to 100,000 gallons - please email for details.
Model | Specification | Price | |
Ichi Super | For ponds up to 2500 gallons. 60 watts power consumption. Dimensions 30 x 15 x 17cm | £495.00 | |
Ni Super | For ponds up to 5000 gallons. 80 watts power consumption. Dimensions 30 x 15 x 17cm | £695.00 | |
Nana Super | For ponds up to 10,000 gallons. 160 watts power consumption. Dimensions 30 x 15 x 17cm | £1095.00 | |
Specification data sheet |

Complete KoiOzone ozone systems
For those who are a little confused, or unsure about what they need to make up a complete working ozone system for their pond, we have decided to offer complete ozone systems which incorporate everything you need to successfully install a working system . These complete systems utilise the simplest and one of the most efficient ozone mixing systems, based round the static mixer, which requires minimal plumbing and no extra pumps or power supplies. This renders the complete system very simple to install. Purchasing a complete working system is not only a convenient way of buying, in that we ensure that you get everything you need , but it will also save you money against buying the individual components. You will receive full installation instructions and comprehensive notes for guidance on the use of the equipment to ensure you get the very best from the system.
Model | Specification | Price | |
Ichi Super complete system | For ponds up to 2000 gallons. 60 watts power consumption. Dimensions 30 x 15 x 17cm. Includes Ichi Super ozone generator, static mixer, Redox controller and probe, kynar non return valve, tubing and connectors. | £812.70 | |
Ni Super complete system | For ponds up to 4000 gallons. 80 watts power consumption. Dimensions 30 x 15 x 17cm. Includes Ni Super ozone generator, static mixer, Redox controller and probe, kynar non return valve, tubing and connectors. | £997.95 |
Oxygen Concentrators
We are delighted to offer, as part of our Ozone range of equipment, a brand new Oxygen concentrator for under £800.00.
Oxygen concentrators work by separating the air we breath into its constituent parts using molecular sieving technology. Normal air is made up of only 28% oxygen, with the remainder being made up of Nitrogen, Carbon Dioxide and other trace gases. When used to supply Ozone generators the normal air we use as a source of oxygen can lead to reduced ozone output, and excessive maintenance requirements since the Nitrogen in air can, in the presence of moisture, form Nitric acid which corrodes the inside of the cells used to produce the Ozone gas more quickly than normal. Also as air comprises only 28% oxygen, for every 20 litres of air supply used as input, only approx. 5 litres maximum of Oxygen is available for conversion to Ozone.
The inclusion of Oxygen generation will therefore increase Ozone output from any Ozone generator to which it is connected by a minimum of 200%, and normally much more than this, so a 1gm Ozone generator with oxygen can be much more efficient than a conventional 2gm system. Increased efficiency is delivered not only because the generators themselves can work at near 100% efficiency, but also because there is much less volume of gas being used. This means firstly that the smaller volume of gas, in this case Oxygen, is more efficiently converted to Ozone and secondly that the Ozone produced mixes much more efficiently in the Ozone reactors or skimmers employed, and there is less Ozone wastage. Ozone reactors can therefore be smaller. In addition to the increased efficiency, cell corrosion is minimised and service intervals increased, your Ozone generator will therefore perform as it should over a much longer period. Also, and particularly for larger systems, inclusion of an oxygen concentrator will reduce the overall cost of the system.
Our Oxygen concentrators can be used with virtually any make and model of Ozone generator on the market, not just our own, and we can guarantee that the efficiency of any system using Oxygen as a feed gas will be increased by a minimum of 200% and more probably by a factor of 300%.
Our latest model of oxygen concentrator now features an up-rated specification, delivering up to 95% pure oxygen at up to 5 lpm, so is now capable of supporting ozone generators up to 8 gm / hr output. It also features a timer, low oxygen output indicator to highight maintenance requirements, and is now much more portable and lighter weight than previous models.
Model | Specification | Price | |
Oxy 5 | Up to 5 litres/minute pure oxygen at 5 psi. Dimensions 50cm h x 27cm w x 44cm d. Weight 16kg. | £795.00 | |
More information |

Air Dryers/Moisture traps
With all corona discharge ozone generators, it is very important to feed them with either cool dry air or oxygen. Achieving a dry air feed is easier said than done, as the average air humidty in the UK is probably around 75% and can increase to over 90%. This means that when using compressed air from an air pump to feed your ozone generator, a certain amount of moisture will be produced in the gas feed line to the generator. Over time, and depending on just how much moisture is involved, the corona discharge cell inside the ozone generator will become contaminated and the ozone output will decrease and the cell will eventually fail. So it's vital to keep the air feed to your ozone generator as cool and dry as possible. You can achieve this in a variety of ways, firstly and most simply ensure that the chosen air pump supplying the feed gas to your ozone generator is rated at no more than 40 lpm - most ozone generators, and certainly those from our range only need between 20 and 40lpm gas flow. Also this should be sited in a cool, dry and well ventilated area. Secondly fit a moisture trap in the air feed line to the generator to trap moisture and enable you to drain this off as required and thirdly to fit an in-line air dryer which we offer in various forms
We can offer a range of moisture traps, and air dryers, from the dessicant air dryer, 500ml capacity (0.5kg approx), to a self regenerating dessicant air dryer to a fully automated electric air dryer
1. Moisture trap 150ml capacity with 6mm gas entry and exit ports (suits 4mm ID silicon or pvc airline) and drain tap. Supplied with wall mounting bracket
2. Dessicant air dryer, 500ml capacity with self indicating dessicant, supplied with 8mm gas entry and exit ports and wall mounting brackets
3.Automatic self draining air dryer, Achievable dew point less than 10 deg c - 220.240v
Specification automatic air dryer:-
- Refrigerant free
- Compact design
- Low noise(58-60dbs)
- Intelligent control
- Low dew point
- Refrigerated by semiconductor without compressor inside, without coolant
- High efficiency heat exchanger
- Heat exchanger temperature real-time display and adjustable
- Easy installation & easy use.
- 0.95amps, 210 watts
- Rated pressure less than 8 bar
- Inlet/Outlet 1/4"
- Drain size 6mm
- Ambient temperature range 0-40 deg c
- Cold chamber temperature 0-10 deg c, adjustable
- Drain time settings 0-9999 seconds
- Drain type, solenoid valve
- Dimensions 310mm x 310mm x 210mm
- Weight 6.3kg
- Maintenance - every 30000 hours
Size | Price | |
150ml | £39.95 | |
500ml | £49.95 | |
Regen | £599.95 |

Above: Moisture trap.

Above: Dessicant filled air dryer.

Above: Automatic air dryer.
Redox Monitors and Controllers and other Ozone system accessories
Redox monitors are important with larger Ozone system installations to check the Redox potential of the pond water. They are also useful to verify the readings obtained by automatic systems. Redox controllers can be added to all of our Ozone generators to produce automatic systems which will control Ozone dosing via user defined Redox levels. The use of ozone requires the use of special ozone resistant materials. We stock special Teflon air line and ozone resistant ceramic air stones and other consumables, such as Redox probes and extension cables.
Model/ Specification |
Price | |
Redox Monitor/Controller - includes switched power centre .
|
£219.50 | |
Redox probe with 3m cable |
£89.50 | |
Redox extension cable 5m |
£19.95 | |
ORP calibration fluid 230mv. Enables calibration and testing of all Redox probes for accuracy |
£9.95 | |
Ozone resistant Teflon tubing 6mm. Priced per metre |
£5.95 | |
Ozone resistant fine bore ceramic air stone 130mm long. Fits 4mm and 6mm push fit connector. |
£11.95 | |
Kynar Ozone resistant non return valve with Viton diaphragm. Fitted into the ozone feed line, prevents any possibility of water syphoning back into the generator. For 4-6mm tubing |
£9.95 | |
Air flow monitor and controller 0 - 200 lph - not suitable for use with ozone gas. | £49.95 |
Above: Redox Controller
Above: Kynar Non Return Valve
Above: Air Flow Controller
Ozone mixing
To get the best from any ozone system, the ozone produced must be mixed in the water flow efficiently. Inefficient mixing can lead to excessive ozone wastage and an unwanted smell of ozone as well as a lower Redox level being attained. Efficient mixing means that you will be able to use a smaller ozone generator, and therefore money spent on a good installation or ozone reactor system will reduce money spent on the generator! Mixing can be achieved in several ways - small ozone generators can simply be attached to special ceramic air stone which are placed in a spare filter chamber or vessel placed at the end of the filter , so that ozone is able to treat the water passing through the filter system before it returns to the pond. Air stones used in this way must be ozone resistant and fine bore ceramic material so that the bubbles produced are very fine - this will give an efficient mix and reduce ozone wastage. A minimum chamber depth of at least 24" is to be recommended if this method of mixing is chosen.
Ozone venturi injectors are now available so that ozone can be drawn into a suitable return pipe and mixed with the returning flow on route to the pond. Venturi injection is an ideal method of ozone mixing for bead and all pressure filter installations, as the pumps required to run these filter systems are already powerful and therefore capable of running venturi mixing systems without further system modifications being required. Venturis are also relatively cheap to purchase and easy to install although because of the pump power required to use them, can be more expensive to run than other types of ozone reactors.
Special protein skimmers or ozone reactors are also available which have been specially designed for use with ozone - these have the added advantage of skimming off unwanted proteins in the water as well as acting as ozone mixing vessels. Protein skimmers are widely used in commercial aquaculture and are available in sizes to suit any ozone installation. They are easy to install and economical to run, as again they only require low power pumps to provide good mixing. However, these devices are much more expensive to purchase than ozone reactors and the process of generating the protein skimming will compromise the ozone mixing to a degree so they generally need to be bigger than the equivalent ozone reactor to produce the same result - too much air passing through a skimmer will reduce mixing efficiency.
Below list a range of ozone reactors, offering all the methods of achieving good ozone mix outlined here.
Venturi Injectors
Ozone venturi injectors work by creating a negative pressure in the integrated air line connection and therefore ozone can be drawn into a suitable return pipe and mixed with the returning flow on route to the pond. Venturi injection is an ideal method of ozone mixing for bead and all pressure filter installations, as the pumps required to run these filter systems are already powerful and therefore capable of running venturi mixing systems without further system modifications being required. Features built in non return valve to avoid reverse gas flow. Venturis can be installed in by-pass piping and so run using an existing filter pump, but can also be set up to used with a dedicated pump and pond return..
Specification | Price | |
KWG 25100 injector 3/4 inch male threaded connection, 6mm-8mm line connection nipple. Gas flow rate 3-10 lpm. Recommended for all ozone generators powered by oxygen.
Dedicated pumps should be medium to high pressure to ensure adequate water flow. |
£39.50 | |
Single Venturi assembly complete for 1.5" imperial pressure pipe. Min length 50cm, min width 30cm. Fitted with model 25100 venturi with compression fitting for 8mm Teflon, 1.5" control ball valve, 2 x 3/4" ball valves on side branch and 3/4" sight glass for easy set up. |
£199.50 | |
Single Venturi assembly complete for 2" imperial pressure pipe. Min length 50cm, min width 30cm. Fitted with model 25100 venturi with compression fitting for 8mm Teflon, 2" control ball valve, 2 x 3/4" ball valves on side branch and 3/4" sight glass for easy set up. |
£219.50 |
Above:Ozone resistant venturi Injector.

Above:Venturi manifold assembly
Static ozone mixer
The mixer comprises a clear PVC mixer tube which contains shear blades designed to agitate and disrupt the water flow which gives good ozone mixing characteristics for smaller systems. May be used with generators up to 1gm output. For best results install horizontally at or above water level and allow 1m of pipe work per gm ozone AFTER the mixing tube and before the water returns to the pond.
Static mixer 50mm dia pipe x 60cm long approx, supplied with 8mm ozone resistant gas fitting, 50mm single union de-mountable connectors and Kynar non return valve
Size | Price | |
60cm | £139.50 |
HD series Pressurised Ozone Reactors
At last we are able to offer top quality pressurised ozone reactors - these units can be used on pretty much any type of system, with gravity or pressurised filters, are relatively compact and very well made. They employ clever technology to introduce ozone into a pressurised reactor and use countercurrent mixing technology combined with a non return exhaust system to allow residual gas to vent to waste without water loss. They employ both forced air (or oxygen) and venturi injection to provide very efficient ozone gas mixing and maximum contact time. Made from Acrylic tube and pvc fittings they are top quality and used widely in industrial applications as well as aquatic applications.
Above: HD200 protein skimmer.
Size | Price | |
Model HD200 reactor | £995.00 | |
Model HD250 reactor | £1199.00 | |
Model HD400 reactor | £2599.00 |
These units can be installed on separate pump fed circuits from, for example, in wall skimmers or can be installed on the main pump fed circuit after the main biofilter. They can be installed at any convenient height and position, either at, above or below water level as they are pressurised devices which provides for very flexible installation options.
Specify the HD200 for ozone output up to 1.5gm / hour, model HD250 for ozone output up to 2.5gm / hour and the HD400 for ozone output of up to 4 gm /hour.
Specification:-
Model HD200 Ozone reactor - 112cm high, 20cm diameter, 40mm water inlet and outlet, 6mm ozone inlet, max recommended flow 1100 gph (5,500 lph). Complete with venturi injection system, non return valve and gas exhaust
Model HD250 Ozone reactor - 112cm high, 25cm diameter, 63mm water inlet and outlet, 6mm ozone inlet, max recommended flow 2200 gph, (10,000 lph). Complete with venturi injection system, ceramic air diffuser, non return valve and gas exhaust.
Model HD400 Ozone reactor - 116cm high, 35cm diameter, 75mm water inlet and outlet, 6mm ozone inlet, max recommended flow 6600 gph, (30,000 lph). Complete with venturi injection system, twin x ceramic air diffuser, non return valve and gas exhaust.

Above: model HD250 ozone reactor.

Above: model HD400 ozone reactor.
Sander Protein Skimmers
There are a number of different protein skimmers which are manufactured especially for use with ozone gas in fresh water. Undoubtedly, the best of these are made by Erwin Sander in Germany. For most Koi pond applications, the Sander Freshskim 200 or Freshskim 300 are the best skimmers to use. They are very efficient devices, and able to not only mix ozone efficiently, but are true protein skimmers and will remove ultra fine solids and dissolved proteins from the water very effectively too.
The pictures (below right) show a Sander Freshskim model 300 protein skimmer installed on our main show pond. This has been coupled to one of our own Ozone systems and the results in terms of water quality are absolutely stunning. You can see from the photos the 'blue' tinge to the water in the skimmer and the mass of bubbles produced in fresh water. The skimmer is powered by an Oase Aquamax 8000 pump for water supply and a Secoh 80 air pump to provide the necessary volume of air required.
Freshskim Skimmers
Sander freshskim models are specifically designed for use with freshwater applications

Sander Freshskim 200 in action mounted on a Nexus 300
Size | Price | |
Freshskim model 200 | £1695.00 | |
Freshskim model 300 | £4595.00 |
Specification:-
Freshskim 200 - 180cm high, 8mm ozone inlet, max recommended flow 700 gph (3,200 lph), recommended for ponds to 6,000 gallons.
Freshskim 300 - 210cm high, 8mm ozone inlet, max recommended flow 1760 gph, (8,000 lph), recommended for ponds to 10,000 gallons
Freight charges for Sander Skimmers will be confirmed with the order acknowledgment and are dependent on delivery postcodes.
