i suffered from chronic ear infections during my childhood, that narrowed my eustachian tubes, making it hard to equalize. my right ear is the worst affected and always gets infected in diving trips, no matter how careful i am.
i got the proear 2000 hoping that it would solve the problem. the truth is, it keeps your ears dry but does not protect them from infection (otitis media).
infection usually results from saliva entering the eustachian tube and eventually the middle ear because of poor equalization results.
what is far more important in avoiding infections is proper equalization. use these guidelines:-
1) equalize as much as possible on the surface
2) descend slowly, let your divemaster and/or buddy wait for you
3) try other equalization techniques, valsalva (taught in PADI) is not very effective. here's an excellent website:-
http://faculty.washington.edu/ekay/MEbaro.html
i prefer the frenzel maneuver, but is difficult with a dry mouth
4) dont be embaressed to abort your dive or stay shallow
again, there is nothing like proper equalization....
regards,