NQL - Basics of bubbles for aeration is smaller is best, but as the size of the bubbles is reduced to a certain point then diffuser clogging of the pores becomes an issue.
Two main things cause pore clogging. 1. Mineral deposits precipitate from the water at the pore location and 2. growth forms at, around, then over the pore. Growth is in the form of bacterial and or algae deposits. This happens even if air is coming out the holes 24/7.
Different materials clog at different rates and at different water chemistries and water clarities.
Quickest clogging materials we have found to be soaker hose then porus ceramic air stones. Slowest clogging materials have been flexable membrane diffusers. The more flexable diffuser "skin" the slower the clogging.
Clogging of the check valve at the diffuser can also be a problem based on structure and compostion of the check valve. To minimize problems and trouble free operation I recommend annual cleaning or at least annual inspection of the diffuser. .
