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7.2.6. PP EVA Pads

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Author : David Bogert

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2 minutes
Difficulty : Level 7

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EVA pads are decent filter media for aquariums and ponds. Japanese mats are not good media.
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.
Symphysodon aequifasciatus discus
Symphysodon aequifasciatus – Discus

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 ft²/ft³ from math“Effective” surface area m²/m³m²/m³ from math
Fluidized K1 medianot tested600na1980na
30 PPI foam1734040011221320
Pot scrubbers1428080924264
Static K1 media13260200858660
20 PPI foamnot tested220180726594
Aquarium gravel6120120396396
Blue Matala pads5100120330396
Eshoppe bioballs510060330198
¼ to ½ inch lava rocks36060198198
Matrix3603019899
Biohome ultimate2403013299
Ceramic rings24040132132
* average ammonia oxidizing that 15 cubic inches (245,81 cm³) of media accomplished over a 90-day period

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. Also the pads disintegrate with time and plug up pumps and filters. We decidedly do not recommend Japanese matting for filter material.