Biological and Mechanical Filtration


The biological capacity of a koi pond filter is a measure of how readily it can convert ammonia and nitrites (which are toxic to koi) into nitrates (which is relatively non toxic to koi). This is accomplished by the nitrosomonas bacteria which breaks down the ammonia and turns it into nitrite. Then the nitrobacter bacteria break down the nitrite and turns it into nitrate, which is consumed by any plants or algae growing in the pond.

The key to making this process work well is to create a good environment for the bacteria to grow in. The Advantage Bead Filter provides an excellent environment for the bacteria by creating a large surface area for the bacteria to grow on. The surface area of a single cubic foot of beads is impressive.


The surface area of one bead is approximately 1/6 of a square inch. There are approximately 325 beads in one cubic inch or 561,600 beads in one cubic foot. Therefore; one cubic foot of beads would have a surface area of 93,600 square inches or 650 square feet. The Advantage 5 Bead Filter, our smallest filter, contains 2.25 cubic feet of beads which would have a biological surface area of approximately 1,463 square feet for bacteria to grow on. That is an area 36′ by 40′, or a bit larger than the surface area of half a tennis court. (The Advantage 15 Bead Filter, with 6 cubic feet of beads, would be twice as large.)

Second, as new bacteria are constantly being produced, the old bacteria can smother it if the old bacteria is not removed. (This is why lava rock filters loose their efficiency after a period of time.) In the Advantage Bead Filter, as soon as the old bacteria dies and let’s loose from the surface of the beads, it is washed away through the backwash cycle allowing the new bacteria to flourish.


How well does it work?

Though the total surface area in the Advantage Bead Filters is impressive, the real question is, how well does it work? Just one of the many tests of the biological capacity of the Advantage Filter was after our buying trip to Japan. When the koi come in from Japan they are brought directly to our residence where we have 5 separate koi ponds. In these ponds, the new koi are treated for three weeks to make sure they are parasite free before bringing them to the shop for sale. The main pond is 9,000 gallons and has one Advantage 15 Bead filter on it. Most of the year this pond is used to keep our largest and most expensive koi for customer viewing by appointment only. For the last nine months, there had been only 18 large koi in this pond.



When the new koi arrived, we moved the 18 large koi to another smaller pond and introduced 130 of the largest and best koi to this pond for treatment. These koi ranged from 16 inches to 26 inches. On the second day, after adding the new koi, there was a slight raise in the nitrite level to a 0.5ppm reading. The next day the nitrite level was back down to zero. On the fourth day we began treatment of the koi for parasites, starting with malachite green and formalin. The pond was treated with 900 ml of malachite green and formalin once every other day for five treatments. With each treatment of the malachite green and formalin, the Advantage Bead Filter was placed on the “recirculate” mode for the first four hours to help protect the bacteria from the high concentration of medication. After the four hours of treatment had passed, the filter was turned back to the filter mode. After the five malachite green and formalin treatments were finished, the salt level was then raised to .3% over the next three days. At that point we added 90ml of Supaverm to the pond. A second treatment of Supaverm was added five days later. During this whole twenty-one day process, except for the slight raise in nitrites on the second day, the ammonia and nitrite levels remained at “0”.



Mechanical Filtering Capacity


Many manufacturer’s claim their filters will give you clear water, but few, if any, ever actually test their filters to prove their claims. At Sacramento Koi, we decided to test both our Advantage Bead Filter and Advantage Glass Filter to see exactly how well they filtered out particles to produce clear water. We contacted Particle Measuring Systems located in Boulder, Colorado, and explained what we wanted to do. They were extremely helpful and sent a representative out to work closely with us in both the setup and testing of our filters. They recommended the “LiQuilaz EZOP Liquid Particle Counter” for our application.

Particle Counter: The LiQuilaz particle counter is designed to accurately sample liquids for a wide range of applications. From batch sampling to in-line monitoring, the LiQuilaz particle counter is capable of measuring particulates in fluids with various refractive indexes, viscosities and operating temperatures. Components of the LiQuilaz particle sensor include an optical bench and electronics. The sensor is capable of detecting particle counts for fifteen channels starting at a minimum sensitivity of 0.2 um. These thresholds are completely adjustable through the software and allow an operator to properly characterize the particle sizes and concentration levels.

The sampled data from the LiQuilaz particle counter are processed using a powerful Windows-based software program, Pharmaceutical Net. This program enables an operator to collect, display, store and report in many different formats. The Pharmaceutical Net program is very flexible for use as a simple monitoring tool or as an advanced analysis package.


The Test



We set up two tanks to test both the Advantage filters and a competitor’s filter at the same time. We added equal amounts of dirty pond water into both the tanks and then used the LiQuilaz Particle Counter to test the water coming through the filters. Additionally, we increased and decreased the water flow through the filters to see if that changed the particle size passing through the filters. We tested the filters over a 30 day period to see if there was any change in the filtering ability after several backwashing cycles.



The Results for the Advantage Filters


After 30 days the test results were extremely impressive. To put things in perspective, Particle Measuring Systems said that the human eye cannot see particles smaller than 40 microns floating in water. The Advantage Bead Filter consistently filtered particles down to 27 microns. Add the Advantage Glass Filter to the system and it filtered out particles down to an amazing 7 microns. This explains why so many people swear by the Advantage filters if you are looking for the clearest water possible.


Sacramento Koi is convinced that there is no other filter on the market today that will give you the incredible water quality combined with the ease of operation that the Advantage line of Filters offer you. This is why we’re willing to offer a one year satisfaction guarantee on all of our filters, and why our competition refuses to match it.