The reason why air diffusers clog. See the following:
1) When air is discharged in water, sludge counterflows into the air discharge opening(s) due to high water pressure.
 Regardless of the air diffusion method or product shape, it is the same for all air diffusers.
2) Sludge counterflow does not equal clogging.
3) More than two air discharge openings cause uneven air flow in their air passage ways causing sludge accumulation.
4) Air dries up the accumulated sludge making it unremovable.
5) The result is air diffusers clog.
The OHR AERATOR does not clog because it has only one large opening which prevents sludge accumulation.

Most air diffuser manufacturers advertise that their air diffusers do not clog. However none of the manufacturers clearly describe the reasons for non-clogging, and they do not show photos of their air diffuser after extended periods of use. (Manufacturers of rubber porous air diffusers claim that rubber shrinks and prevents counterflow of activated sludge into their air diffusers. However, porous air diffusers always clog within several months to several years. Hence this explanation is completely untrue and totally misleading.)
The reason rubber porous air diffusers clog, see page 16 of our ‘8 point detailed guide to air diffuser selection’.

8 point detailed guide to air diffuser selection (PDF)

There are now many vertical air diffusers on the market, which have large air discharge opening(s) and inside structures. Some vertical air diffusers have more than one air discharge opening. This means that the blown air has to pass through narrow branching airflow paths inside the air diffusers before being discharged, causing sludge accumulation in the air passage ways due to weak uneven air distribution. The sludge will accumulate and dry up inside the air diffusers due to hot air that can exceed 80°C in the summer) causing clogging. This is the same reason rubber porous air diffusers clog.
There are also vertical air diffusers that catch bio-carriers for MBBR system or trash (i.e. fallen leaves) unintendedly because of their complicated and overdense inside structures. Unlike rubber porous air diffusers, vertical air diffusers suck activated sludge into their inside structures causing clogging if their inside structures are too complicated and overdense.

The reason the OHR AERATOR does not clog, see page 17 of our ‘8 point detailed guide to air diffuser selection’.

8 point detailed guide to air diffuser selection (PDF)

If you select the wrong air diffuser it will clog and you will have to replace it periodically. The wastewater treatment condition will deteriorate due to air diffuser clogging and hinder the stable operation of your factory.
Rubber porous air diffusers are famous for clogging, but it is not so well known that vertical air diffusers can clog because they are new to the market. Please be mindful of this issue.