I had problems in the beginning. Equalizing, water in the ear and a few infections. Now I do the following. 2 days before a dive, or dive trip, I start using Claritin, or similar. I take one every day right through the day of the dives or the dive trip. Also, keep the water OUT of your ears. How? Doc’s Pro Plugs (vented of course) or Aqua Seals. I will not dive without them, especially cold water. A ENT specialist told me to avoid cold water in the inner ear if at all possible. I still need a little more time than most to equalize, but the issue is behind me and I do not fear any ear/sinus problems. Hope this helps.
PS - Some buddies who took my advice now swear by the plugs and decongestant program. Good luck and safe diving......... Joe P