Best hearing aids high frequency loss

Yes, but "mixed hearing loss" is quite big category. But what is the cause of hearing loss, especially the conductive part of hearing loss?

I think fluid behind the ear that's why I'm having grommets put in

But what is the cause of that fluid? Recurrent infections? Localised inflammations? Eustachian disfunction and more? Still too little information for getting the whole picture.

I do get ear infection quite often iv been told Eustachian disfunction and fluid behind the ear