Yes, the rolls are thicker than I expected. Initially, I was hoping that they would be three or four inches thick, but I assume that six inches will be alright. I will simply adjust what I had in mind for my filter design modification.
Originally I was going to have my first 55 gallon HDPE barrel filter act as a debris and sediment trap prior to the Kaldness K3 bio-converter. I was going to use layers of varying rock sizes to perform some mechanical filtration and provide a "speed bump" to cut the water velocity so that some of the solids would drop out of the water before the water continued on to the bio-converter.
After pondering the use of the rocks for this purpose, I thought that it might prove to be less user friendly. Should I desire to remove the rock to relocate my system or clean it, it would be a labor intensive chore. Not hard work, but just messy and tedious. So, I started contemplating the MATALA media to replace the rock.
The 22" diameter MATALA rolls would fit perfectly inside my 55 gallon barrels. They will be snug enough so that water won't pass around the outside of the the barrel between the media and the barrel wall and not so tight that I have to fight with them to get them into place.
Now I can use the varying densities of the MATALA media to simulate the varying sizes of rock and gain several advantages. 1] Lighter in weight. 2] Uniform. 3] One piece. 4] Higher water pass-through volume. 5] Greater efficiency and use of space. 6] Easier to clean. 7] Provides both mechanical filtering as well as bio-conversion (bacteria habitat). The rock would do both as well, but I believe the MATALA will be much better at it.
8] More versatile or accommodating to design alterations. It will be a lot easier to make changes if I find out I calculated water flow volume incorrectly.
The disadvantages I can cite are expense (about $58/roll), longevity (rocks are forever) and quick access. I can get the rock just a few miles down the road at a dirt cheap price.
I talked myself into the MATALA media rolls yesterday and ordered some. USA Koi seemed to have the best price all around for half sheets, full sheets and rolls, so I ordered from them.
I wish that the rolls were 4 inches thick instead of six. This is due to my barrel filter design. I wanted to take advantage of at least three if not all four of the MATALA media densities (black, green, blue and gray). But, because of the depth of the barrel (36") the six inch rolls would take up a lot of space. It's an upflow design and I need 6 inches bottom footer space and approximately 8-9 inches header space in the barrel. That leaves 21" space for the media. That means no more than three rolls (the fourth roll won't fit - but only just barely). At four inches, I could fit five rolls in the barrel perfectly.
I decided to go with just two rolls to start and experiment with that first (one green and one blue). I can then adjust for a third roll later if I find it necessary. If the rolls were four inches thick, I would use all four densities right off the bat and still have room for one more roll of whichever density I found necessary. I ordered a third roll (an extra blue density roll) just to have it already on hand for experimental purposes, but I will see what happens with just two rolls first.
Come spring or early summer, I will have it all assembled as a prototype and by the end of summer / late fall I will know how well it works. Many other design parameters to work on as well. This is just one small part of the whole project.
Gordy
