Aerating, filter question

Hello Grizz and all, thanks so much for the research and this wonderful place! My folks have a small rental house that appears to need a new leach field, having to be pumped out every few months. My current thought, after reading your bad experience with aerating, is to attempt prototyping a special type of outflow mechanized filter with durable medium that automatically water jet backwashes itself periodically. By this, I was hoping to attain a very fine particle filtration capability to prevent the potential leach field problems from aerating/stirring up the single tank. Any thoughts, and could you suggest how small of particles I should be aiming to filter to prevent leach field damage?
Thanks!
Jesse