Choosing an Aqua Ultraviolet Ultima II Filter

The Aqua Ultraviolet Ultima II filters are one of our favorite combination mechanical/biological filtrations systems. This filter is quick to install, and works excellent for various sized ponds at filtering out solids as well as converting harmful ammonia into fish and plant safe compounds. In addition, with the self-cleaning backwash cycle, cleaning is fast and easy.

choosing an aqua ultraviolet filter

Another reason we like the Aqua Ultraviolet Ultima II filter is the filter media. Not only does it come pre-seeded with beneficial bacteria to get the biological filter off to a good start, but the filter media shape and material really helps prevent clumping like you might experience in some other filters. There’s really nothing worse than clogs or clumps which allow the water to pass around the media unfiltered, or worse, prevent water from getting through the filter all together.

Choosing the Correct Size of Aqua Ultraviolet Ultima II

Ultima II SizePond Size (gal)Min/Max FlowPump RecommendationBuy
Ultima II 1,000 500 - 1,000 500/1200 GPH 1,000 GPH at 10’ of Head  More info 
Ultima II 2,000 1,000 - 2,000 1,000/2,500 GPH 2,000 GPH at 10’ of Head  More info
Ultima II 4,000 2,000 - 4,000 2,000/4,500 GPH 2,000 GPH at 10’ of Head  More info
Ultima II 6,000 4,000 - 6,000 3,000/7,500 GPH 6,000 GPH at 10’ of Head  More info
Ultima II 10,000 6,000 - 10,000 5,000/7,500 GPH 7,500 GPH at 10’ of Head  More info
Ultima II 20,000 10,000 - 20,000 7,000/7,500 GPH 7,500 GPH at 10’ of Head  More info
Ultima II 30,000 20,000 - 30,000 7,000/7,500 GPH 7,500 GPH at 10’ of Head  More info
Ultima II 30,000SMV 20,000 - 30,000 10,000/20,400 GPH 15,500 GPH at 10’ of Head  More info
Ultima II 60,000SMV 30,000 - 60,000 15,000/20,400 GPH 20,500 GPH at 10’ of Head  More info
Ultima II 100,000 60,000 - 100,000 20,000/24,400 GPH 24,000 GPH at 10’ of Head  More info

Choosing a Filter Size – Pond Size (Water Volume)

The first step to figuring out what size of Aqua Ultraviolet Ultima II you need is to calculate or measure the amount of water in your pond. An easy way to measure the volume of water in a pond is to purchase a water flow meter, which provides a digital readout of how much water has passed through the device when attached to the end of a hose. Or if you’re good with math, you should be able to calculate an approximate volume from the length, width and depth of your pond.

Choosing a Filter Size – Flow Rate

The second step to choosing an Aqua Ultraviolet Ultima II is to decide on what kind of flow rate you would like achieve. It’s a good idea to plan your system so that it’s capable to turning over the entire contents of your pond every hour. What that means is that if your pond is 1000 galons, then you should aim to pump and filter at a rate of 1000 g/hour.

Choosing a Filter – Head Pressure

It’s important to keep in mind that every pumping system contains certain forces and pressures that work against the power of the pump. Examples include rises in elevation from the intake of the pumping system to where the water is returned to the pond (like in the case of a waterfall), or corners and fittings in the pipe work. When choosing a pump, it’s very important to choose a pump that is capable of pumping your target flow rate AFTER taking into considering the head pressure of your system. To learn more about calculating head pressure, please see our page here.

Once you know your water volume and flow rate, simply use the above chart to figure out what size of Aqua Ultraviolet Ultima II filter you will need.


Frequently Asked Questions

How is the Aqua Ultraviolet Ultima II Different than a Bead Filter?

Many bead filters are prone to clumping due to the inexpensive, smoothly shaped wax based pellets used as filter media. When the beads stick together, water and waste pass around the clump, rendering the filter ineffective at filtering out solids and ammonia. Using non-wax based plastic, Aqua Ultraviolet extrudes a patented media with the highest surface area of any filter media on the market. The small tubular design has ridges on the outside and a cross section on the inside, which greatly increases the surface area for biological filtration, as well as prevents clumping of the filter media. In addition, the ridged design helps to create a dense bed for superior trapping of solids that are easily separated during the backwash.

How can the Aqua Ultraviolet Ultima II filter be smaller than a bead filter and yet support more fish (ie. filter more effectively)?

The Aqua Ultraviolet Ultima II patented media design has 800 cubic feet of surface area per square foot. This is the highest surface area of any product on the market. The high surface area means less volume of media is needed so the filter itself can be smaller

Will this filter clear up my green pond water?

There are few factors that can contribute to green pond water. The two most common factors are too much sun exposure and an inadequate or improperly operating biological filtration system. Purchasing an Aqua Ultraviolet filter will definitely take care of the biological and mechanical filtration aspect which is a very common reason for green water. However, one should keep in mind that green pond water is caused by an accumulation of millions of single cell, microscopic spores of green algae. These spores are fueled and reproduce through photosynthesis, which is made possibly by sunlight from the sun. If your pond is receiving too much sunlight in a day, that could also be stimulating an 'algae bloom' in your pond. To learn more, please see our page on green pond water.

Will this filter eliminate string algae/hair algae/blanketweed?

String algae is a common problem in even healthy ponds. Although an Aqua Ultraviolet Ultima II filter will definitely help your overall pond ecosystem, it will not eliminate string algae entirely. Please see our page on string algae to learn about a few potential remedies.

Can I use this filter in a swimming pool, or in salt water?

No. This filter is meant for fresh water ponds only.

How often does the media have to be replaced?

The media should never have to be replaced under normal use.

Can a Aqua Ultraviolet Ultima II filter be buried to conceal in landscaping?

Yes, the filter can be buried up to the valve to help hide the filter within your pond landscape.

During the backwash cycle, does the beneficial bacteria colony get damaged?

Due to the shape and material type of the filter media, the bacteria is protected during the backwash cycle. Feel free to backwash when necessary without damaging the culture.

How long does it take for an Aqua Ultraviolet Ultima II filter to start working?

Independent lab tests have shown that the Aqua Ultraviolet Ultima II is capable of converting ammonia to safe compounds within 2 to 4 weeks after installation. This is actually quite reasonable compared to other forms of biological filtration. Some other brands can take up to 5 or 6 weeks for the ammonia conversion process to optimize.

Still have questions? Send us an email and we'll back to you as soon as we can!

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