Low Density Black Matala
The Black Matala can be used as a support grate for other layers of media due to its very sturdy and open design. The Black Matala is used widely as a large particle size solids filter. A single layer 1.5 inch thick can filter out things like leaves, large clumps of algae, cigarette butts, seed pods, etc. However, if you use multiple layers it can really filter out some smaller particles like medium size koi pellets, small bits of algae, tiny leaves and plant debris, etc. The Black Matala is highly under utilized. We have designed filter tanks with 4 to 6 layers of Black Matala (6in. to 9 in. thick) as a prefilter with flow rates approximately 10 gallons per minute per square foot and essentially nothing but the finest dust particles get through. The flow rate per square foot is very important. In a settling chamber a single layer of Black will slow down and trap large particles and hair algae. Each additional layer you add will trap a smaller and smaller particle without clogging. That’s the big advantage to Matala media in general, if you use it correctly, it can hold tremendous amounts of debris without clogging.
As a side note, the Black Matala is actually the most used density for waste water treatment / sewage systems. It is currently being used in municipal waste water treatment plants in various cities around the world. The open flow configuration allows high volumes of dirty water with very high biological oxygen demand to pass through without clogging. The bacteria growing on these strands form thick biofilms in an oxygenated environment with even flow distribution.
When you use the Black or Green Matala for mechanical / solids filtering, you may use the garden hose to spray them clean. In general these two color densities are use as mechanical solids filter pads and you are not concerned with losing any bacteria with a hose washing. The dirt falls off very easily.