trimix

I used to have this problem too, but not anymore.
A few years ago I was dabbling with freediving, and found pretty quickly that when using the Valsalva technique as I always had while on SCUBA, I could not equalize with my head horizontal or down from horizontal... apparently common.
I had to learn a new technique to equalize, and since learning that method, when I dive scuba equalizing is almost effortless in any position, is quicker and more effective - I actually dive when I'm still stuffed up after a cold, with no decongestants (yes I know about reverse squeeze -I'm talking about equalizing here!)
The technique is called 'Frensell', which you can look up on the interweb-thingy. It took quite a while to master, but once I did, it was like a Eureka! moment, and seemed so obvious! I still have to pinch my nose, but I do not blow - Basically it involves using the back part of your tongue to compress the little bit of air in your throat and sinuses - POP! I can repeat the motion more than twice every second, which is handy when freediving down to 45m head down. Also handy for a quick EQ@ when managing descent, suit squeeze, finning off the wall and signalling buddies, all at the same time.
Look it up and try it - it's much less strain than Valsalva. Good luck, keep trying!

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