Membrane or porous

Membrane or porous materials?

• Far more pressure is needed to open the slits and diffuse air trough a membrane than diffusing air through a porous material.
  More pressure loss means lower efficiency.
• When shutting off the air pump a membrane closes so dirt can’t enter. This is unlike porous material where fine sediment can enter the aerator.
  For intermittent aeration membranes are more suitable.
• A membrane suffers from mechanical wear and tear unlike porous materials which do not suffer these effects.
  Porous materials are therefore more durable.
• A membrane has a limited permeability. Therefore, the permitted airflow is lower than that of a porous material. There are more membranes required for the same amount of airflow.
• Accumulation is purely related to the raw material choice of the membrane or porous material.
• A membrane is flexible and can lose accumulation with movement.
  On the other hand membranes are vulnerable and can not be cleaned like HDPE diffusers which can be cleaned with a pressure washer.

Out of what material are the Oxydent diffusers made and why?

• Oxydent uses porous material made of HDPE for the production of the diffusers. The reason to choose this material is very low pressure loss, very smooth surface which hardly allows fouling and very high permitted air flow. Also it does not require replacement due to wear, making them reliable.
• Ceramic materials are commonly only used for air stones in aquariums. For professional applications, they are too weak and unreliable. HDPE is therefore preferred. If the circumstances require membranes, (like with intermittent aeration) Oxydent uses PU membranes. These have the highest chemical and UV resistance and from all the membrane materials the are the strongest.
• EPDM membranes such as those offered in many disk aerators are especially popular because they are very cheap to produce and need to be replaced regularly. This is an advantage for the manufacturer. Oxydent uses PU to insure durability and quality.
• Silicone is water resistant which has a coalescing effect on the bubbles and also it is less strong than PU. PU is therefore preferred.