The data from the master table for PP and EVA pads is:
This calculation is extremely rough as these pads vary considerably in the degree of reticulation and in the pore size. But it appears by testing that this data is relatively good for the Matala blue EVA pads.
There are a whole series of bonded semi-rigid fiber mats or pads sold for filtration. The very coarse open pads are made of polyester fibers, PP (polypropylene) or EVA (ethylene vinyl acetate) plastic. Matala pads and Japanese mats are probably the two versions used most. Their cost is $40 to $80 per cubic foot and $26 to $72 per 100 square feet of biofiltration surface so they are a viable option for both a submerged static biofilter and a trickle filter.
We tested the blue Matala pads in a test of filter media with regards to ammonia oxidizing capability. The pads came out quite surprisingly well in the test. This means they are viable candidates for biomedia in things like canisters and sumps.
A test of ammonia oxidizing capability of various filter media was run. The first number, the “efficiency” is the average ammonia oxidizing that 15 cubic inches of media accomplished over a 90-day period. The second number is the “effective” surface area in square feet per cubic feet calculated from that test. The third number is the effective surface area in square feet per cubic feet calculated by simple mathematics. The correlation between the test results and the calculated surface area is very significant and means the testing was accurate.
| Media | “Efficiency” from two tests | “Effective” surface area ft²/ft³ | Effective” surface area cm²/cm³ | ft²/ft³ from math | cm²/cm³ from math |
|---|---|---|---|---|---|
| Fluidized K1 media | not tested | 540 | na | na | |
| 30 PPI foam | 17 | 340 | 400 | ||
| Pot scrubbers | 14 | 280 | 80 | ||
| Static K1 media | 13 | 260 | 200 | ||
| 20 PPI foam | not tested | 220 | 180 | ||
| Aquarium gravel | 6 | 120 | 120 | ||
| Blue Matala pads | 5 | 100 | 120 | ||
| Eshoppe bioballs | 5 | 100 | 60 | ||
| ¼ to ½ inch lava rocks | 3 | 60 | 60 | ||
| Matrix | 3 | 60 | 30 | ||
| Biohome ultimate | 2 | 40 | 30 | ||
| Ceramic rings | 2 | 40 | 40 |
The higher the numbers here the better the media. This makes 30 ppi foam the best static media for canisters and ceramic rings the worst. The Blue Matala pads had decent performance.
The polyester fibers in Japanese matting are very thin and the density of the product is very low. While we didn’t test these mats we suspect they will not perform as well as Matala pads. The pads are just too open to retain much in the way of brown gunk.
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