For Ponds 2,000 to 4,000 gallons (7,570 L to 15,140 L). See other sizes of this filter.
Just minutes to Backwash without having to get your hands dirty
Preseeded with beneficial bacteria to start colonization quickly
Available in 2 different valve sizes - 1-1/2" and 2" (choose option above).
To maintain a healthy pond ecosystem, it is important to remove both ammonia and accumulated debris. The Ultima II filter series combines both biological and mechanical filtration in one compact body. The patented media has the highest biofilm surface for bacterial growth. This beneficial bacteria converts ammonia into harmless compounds which are returned to your pond water. As a mechanical filter, the dense bed of ridged media traps solids efficiently without clumping. Cleaning is a simple process with the integrated backwash cycle. By simply rotating a valve, internal jets in the filter are activated, which separate out the waste from the media, sending it out the waste line.
The ideal pump would be capable of pumping 2000 gph (7,570 lph) under 10' of head pressure. The minimum flow required is 2000 gph (galons per hour), and the maximum flow recommended for the filter is 4500 gph. The filter runs best within this range, so be sure to choose a pump that will pump the desired amount after taking into consideration the head pressure of your pumping system. To learn more about head pressure and now to calculate it for your pond, click here.
Frequently Asked Questions
How is the 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 Ultima II filter be smaller than a bead filter and yet support more fish (ie. filter more effectively)?
The 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 this 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 this 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 Ultima II filter to start working?
Independent lab tests have shown that the 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.
Type of Filter
2000 to 4500 GPH
2000 to 4000 gallons
Inlet / Outlet
Either 1 1/2" or 2" (choose option above)
Max Head of Pump
Yes, Aqua UV tubular media, pre-seeded with natural bacteria
Built in UV Light Power
None - See external Aqua UV Clarifiers
Electrical Cord Length
20 1/2" Dia. x 38" H
One year from the date of purchase
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