[bekko]

James, I agree they would be better than bottle caps in a TT application, but bottle caps are better in a submerged nitrification application because you can make a moving bed. Bottle caps do not have the surface area of Kaldnes, but they will move with less aeration energy because they catch air and force their way to the surface - pushing everything else aside. Punching holes might defeat that. I also thought you had the larger size bio-barrel (1.5 inch diameter).

For a TT arrangement, my poor-man's preference is still coral rubble. It provides lots of surface, micro-niches, buffering, and yellow cosmic rays. A little heavier than plastic, but that is not really a concern in a TT.

-s t e v

Quote: Originally Posted by JasPR Bioballasts have been around for a generation and are used in both oil recovery area and in the waste treatment industry. In the 1980s they were being bought in bulk by ornamental fish industry folks and broken into small packaging for the hobbyist ( and then sold for a fortune!) and also used in TT applications at modern trout farms. The size is KEY, with the 1/2 and 1 inch castings giving the most surface space compared to the 'fist size' units made for waste treatment. Because they are made for massive applications, a typical order is by the truck load. I buy large boxes full ( almost the size of a home washing machine) for about $75. On this price you need to add a $150 'nuisance tax' in the form of a handling charge. But this is a fixed cost so it can be amortized over several boxes- this explains WHY I have six full unused boxed in my garage! LOls These are ideal for TTs as they are untrapping, unlike bottle caps that would hold water pools and also be trapping ( a counter productive thing in a TT). A koi pond is about both organic and inorganic waste management and bottle caps will trap due to one closed end. They will also not allow for self cleaning the way a bioballast would. See picture below for packing characteristics of bioballasts-- Steve, the reason you would need blocking with TP in a waste treatment application is because they are non trapping and the flocs need both retention time and organic accumulation. We, on teh other hand , need the opposite for inorganic management. We separate out inorganic and organic processing and are therefore needing different applications. One of the tests for a long term self sustaining biofilter is it's ability to cleanse itself. TTs give flow and spaced Jmat even give flow so that natural mechanical and genetically programmed sloughing ( a form of 'shedding' needed for healthy biofilm) of the biofilm surface can take place. A closed end bottle cap will not allow for this and organic fouling is greatly increased, changing the nature of the biofilm over time. In addition, efficiency of a biofilm is directly effected by media design. You want eddies within and around biofilm- and NEVER any dead space. If one really wanted to use bottle caps then perhaps placing the caps on the bottle and using a hobby soldering tool to punch-heat several holes thru the top might create a better design. JR