Biological filtration is one of the cornerstones of water quality in any enthusiast’s koi pond. Some might argue that it is the alpha in clean water.
Changing the lethal waste product of Ammonia (enthusiast: turns, spits) to its less lethal step-sibling Nitrite and finally into the somewhat less-destructive Nitrate is all part of the Nitrogen Cycle. It helps to ensure that your koi can live a long and healthy life in clean koi pond water, providing hours more pleasure (which may or may not be laced with some anxiety).
Enter the Zakki Shower. If the name sounds familiar, it is because the name is a mixture of the creator’s name, Zac Penn, and a Japanese gravity-fed bio-filter, the Bakki Shower.
The two showers share similar principles in that they both rely on pond water being distributed (usually through slots or sprayed) across the top of porous (or rock) filtration media. The media provides a safe haven for all of the beneficial bacteria that remove the different phases of nitrogen waste from the water.
Additionally, by allowing the water to “crash” across the media, the water is further oxidized (one of the necessary ingredients for the nitrogen cycle to function) to help with the purification process.
The main difference in the design is that, unlike the Bakki Shower, which utilizes a series of trays below one another, the Zakki shower only has one tray. It is a single-level filter that can handle between 8-15,000gph.
The Zakki shower’s flagship is the standard 49×20.5×20” model. But the manufacturing company, Deepwater Koi Innovations, advertises that they can be customized to fit different needs and koi pond requirements.
Part of the Zakki shower’s charm is the aesthetic value as well as the amount of space it takes up. The single tank can be placed at the side of a koi pond, and with the weir option, functions as a water feature. Bakki Showers, because they can be up to 4 trays deep, take up space that some enthusiasts might not have, and are not as pleasing on the eye.
The Zakki shower boasts an open-air media tray that comes standard with all of the different models. The open air trays have thousands of holes in them. These holes are reported to aid gas exchange more efficiently (degassing) than the trays used by Bakki showers, which are solid with no holes in them.
True Bakki Showers use Bacteria House Media (BHM) by Momotaro. This reputed Koi farm developed this kiln-fired porous media and enthusiasts swear by its ability to get great water quality. However, many are put off by the cost of the media. In a four stack Bakki shower, 20lbs+ of Momotaro media is used in each of the trays, making it both expensive and heavy. There are alternative (and less expensive) types of media like feather rock, pumice rock, lava rock or Chinese ceramic media and Crystal Bio (made by another Japanese koi farm from porous glass-like media).
In the case of the Zakki Shower, it relies on a porous man-made ceramic media called Cermedia.
Thanks to the interconnected pores, it boasts an impressive square footage of bacteria-laden material for a relationally much smaller piece of media, allowing it to house more beneficial bacteria in a smaller “package” of media. It also helps to keep the weight of the tray down.
The one detraction is that the Cermedia is not reliable and will eventually turn into a gooey mess inside the basket itself.
The biggest issue I have is with Cermedia. There are people who swear by it but there is a huge group of people it is failing. The media clogs and then disintegrates.
Alternatives could be sought, but the square footage of surface area that the Cermedia achieves is integral to retaining the Zakki shower’s compactness, and the replacement media might not suffice in keeping the water parameters. The manufacturer also will replace the media.
I had some break down of my media and they sent replacement media free, more than what actually broke apart. So far it’s held up really well. I just cleaned all of the media and shower the other day, and you couldn’t make a 1 by 1 cube with what came off. Everyone has different experiences, though.
As in all filtration choices, there are those that have huge success with a particular type of filtration and swear by it, and those that are hasty to point out any inherent shortcomings. But in the end, it all comes down to the quality of your water and the health of your koi. Finding something that works into your budget, space, and sense of aesthetics can be a tricky balance, so it is nice to have options.