Sweetwater diffusers are the highest quality ceramic-type air diffusers on the market today. They're machined from a solid block of glass-bonded silica. Because dust and dirt particles up to 30 microns in size will pass right through these diffusers, there's no need for expensive air filters. With their round grain pore structure, low resistance to air flow, uniform porosity and resistance to clogging, Sweetwater diffusers are clearly the best diffusers available for general aquaculture aeration. Smaller pores don't necessarily produce smaller bubbles. Sweetwater diffusers are engineered to produce the smallest bubble possible within the constraints of a reasonable service life. In most soft water applications, they won't need to be cleaned for more than a year. Note that water pH in excess of 9.0 will shorten the diffuser life. Self-weighting when used with typical tubing lengths. Info from AES.