[TheDude]

I'm not an expert as well, but from my experience your problem can have various reasons, for example
- one eustachian tube smaller in diameter than the other
- swollen eustachian tube or inner ear
- mucus in the sinuses

Sudafet is a drug containing pseudoephedrine, which very simply said dries the nasal membranes of mucus. So basically it helps if your nose and sinuses are full of mucus or swollen. But keep in mind that drugs and diving is not a very good mix, it can help, but I would not use it regularly.

There are two things you can do
- learn proper equalizing technique -> Frenzel (which can produce higher pressure for equalizing with less effort, and so equalize even "difficult" ears)
- try Jala Neti - which is a yoga technique for cleaning sinuses by flushing them with salt water. It is sort of disgusting the first few tries and has to be used on a long term basis, but I can higly recommend it, helped me very well.