Koi Pond Shower Filter

by Richard Renshaw

Picture of Mini Shower Filter

You can not have a discussion about Koi pond shower filters without mentioning the Bakki Shower filter.

Picture of Bakki Shower & Bacteria House

The Bakki Shower filter was developed by the Momotaro Japanese Koi farm. The Bakki Shower filter was designed with stainless steel trays and incorporates Bacteria House ceramic media. There are many DIY shower filters built with plastic, fiberglass, and stainless steel boxes called "Bakki" shower filters. I do not consider a shower filter with lava rock media a "Bakki" shower filter.

So what is the difference between a shower filter and a trickle filter?
I think the primary difference is the flow rate. Shower and trickle filters are great at biological filtration.

I am a big fan of DIY shower filters. I have and still use a packed column shower filter built out of a larger 10 - 12 inch diameter, 5 - 6 feet tall PVC pipe with plastic filter media inside.

What is the difference between a shower filter and a packed column filter?
The primary difference is the use of "trays" vs. one tall packed column. Packed column filters can be degassing columns that are designed to strip out undesirable gases. The design of these units also make them very suitable for biological filtration.

The advantage shower filters have over other submerged media biological filters is the shower media is exposed to more oxygen. Like Koi, the bacteria living on biological filter media need plenty of oxygen. There is also the benefit that the water from a shower filter is aerated which benefits the pond.
The disadvantage to shower filters is the pump has to lift the water higher and there can be some pond water cooling effect.

Like many other DIY shower filter builders, I needed and was looking for some inexpensive plastic trays to use. I was looking for something in the 24" - 36" long size that would hold around a cubic foot of filter media. I wanted trays that I could stack 2 - 3 high. What I found was an inexpensive square plastic planter box at Lowe's. The cost was $14.97 and the planter boxes are made by Fiskars.

Picture of Fiskars Veranda planter

The Fiskars 18" Veranda square planter box is 18" x 18" x 14" tall. The inside dimensions, below the "step" in the side, is approximately 13" x 13" x 8.5" tall. That is about the same volume as a 24" x 8" x 7.5" tall tray.

There are many choices for shower filter media. The very best performance would probably come from using Cermedia Marine Pure ceramic media. Like the Bakki Shower Bacteria House ceramic media, the Cermedia Marine Pure ceramic media is probably the most expensive choice for media. The problem with using Cermedia Marine Pure ceramic media is the pond water needs to be more mechanically filtered (removal of the finer particles) before entering the shower filter.

Other popular choices for shower filter media are lava or feather rock or plastic media. The choice of media will affect the cost and performance. Different plastic media will have different biological filter performance in a shower filter. Not all bio-balls will perform the same and more bio-ball rated surface area is not a guarantee of more biological performance in a shower filter.

For "bio-ball media" for shower filters, I like bio barrels (also called pall rings).

For this mini shower filter, I decided to experiment with using some used bio barrels I had in the top tray and lava rock in the lower tray. The top tray is packed with bio barrels which work very good in packed columns and distribute the water good (as evident by the even water flow out the bottom of the tray).

For the bottom tray, feather rock was my first choice, but availability of the size I wanted became an issue, so I went with lava rock. When I went on my search for lava rock in the garden centers, I happened to ask a sales cashier at Home Depot; "Where would I find lava rock?" She directed me to the barbecue grill section where I found small bags of lava rock for barbecue grills.

I like the size of the "rocks" better than the decorative lava rock sold in the garden section.

I should mention that after I built my mini shower filter I discovered that it resembles the Bridge Way Koi's BaWaKi Shower filter.

I can assure you that I was not trying to copy the BaWaKi Shower filter and the BaWaKi Shower filter is much bigger and better built than my DIY mini shower filter.

How I Constructed My Mini Shower Filter

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Copyright © 2013 by Richard L. Renshaw