Maybe some of you will find this interesting. Its simply a combination of my two favorate methods of Bio Filtration, IMHO, they are the only methods that I consider good practice in the Koi hobby. The only reason for the combination here is that I needed space for my Sacramento Koi Bead filter, and for my former aerated moving bed in 55 gal drum, which will this season I will use to continue my tests of static K1 (which is not working to well for me so far). Some people that need a powerfull filter in a small footprint may find this interesting. I built a little frame around the whole thing, waiting for some vines to grow around it. These types of filters are not only superior in performance, but also in maintenance. Depending on the media, a TT/Shower can go years between any maintenance. In theory, a aerated K1 moving bed should never need any media cleaning maintenance, but needs a partial tank flush anywhere from once a week to once a month.
I've been running TTs or Showers since I started with ponds 2 years ago with a 220gal goldfish pond, and was introduced to the technology by a fellow ponder (Griff). Griff has had tremendous results from this types of filters in water quality, water clarity, and Koi growth. On my small goldfish pond I run a 1cuft cylinder type TT. It has a Lava Rock frame but is filled with K1 that has been in place for a little over a year now. My Koi pond has ran 2 large TTs, roughly 4.5cuft each. Cylinder type, Egg Rock shell (for looks) filled with Lava Rock first year, 2nd year with K1 and Bio balls. The crate system, although more expensive, is better from a maintenance perspective. I choose the small "donut trays", they give me plenty of gaps, good air exchange, and are small enough that Lava Rock is easy to handle in them. I appear to get better performance from Lava Rock, so wanted to go back to this in a way that is easy to maintain.
The Combo: Most of this was build last year, now that time and weather is comming around I cut everything on this weekend. The moving bed part has been running for a month now. As I said earlier the reason for the combo is footprint of the filter. The idea started looking for a base for the TT/Shower, I was going to have to use a stock tank (70gal) for this anyways, so that is how the project started into using a larger tank and moving bed here.
Rough diagram from last year for illustration: