Here's what my experience has been. Norm (Scrmnkg) installed a shower filter on my 5000 gallon pond in December 2008. Initially, we used the Stak-Pak containers from US Plastics, and (for water and sound containment) we used a half-tray upside down on top as a lid. For additional air, Norm drilled a total of four holes in the upper part of the long sides and glued on ells facing down. Media is Bacteria House (I think I scored the last batch of it in the U.S.
) The spray bar has three rows of holes drilled. Flow at the outset was roughly 6000 gallons/hour from my two no-niche skimmers, going first through two barrels of Bacti-Twist. I had consistent nitrate readings of about 10 ppm with this setup. (The other circuit of my filtration is two aerated Koitoilets to two Cetuses, which then combine to go through one Sac 10, then UV, then TPRs.)
In mid-April of this year, Norm switched out the Stak-pak trays for Birdman's open-top fiberglass ones, using the same media; the flow rate was cut to 3000 gallons/hour because my second skimmer was diverted to the sand/gravel filter he set up in the barrels at the same time. The bottom tray is stuffed with the Bacti-Twist media that we had left over from the original barrel setup (this was done for sound absorption). Three weeks later, my nitrate was 0. In the three months since the change, the media has developed a thick patina of biofilm, where it was a really light coating before. I can't say whether it was the extra air or the slower flow that made the difference; I know the s/g filters also have bio properties, but three weeks seems kinda fast for that particular conversion.
I'm no chemist, and I'm not sure I'm a believer in the Far Infrared Radiation properties
of the Bacteria House media. What I do like is my -0- readings, and the fact that I have extra oxygen going to my pond. The Bacti-Twist in the bottom tray has actually made the open trays quieter than the Stak-Paks were, and it's perfectly pleasant to sit out on the deck right in front of the shower filter.