Hmm. weird. I'm about 200 mi. inland from the coast, so maybe you're more coastal than I am.
I'd be curious what Soil King's "Big Roots" would do for you...and me. hehe
I'll still be mixing my own dude to $ constraints...but I'd probably try that or the top of the line ProMix if I had the options.
FWIW, Oregon's Only came packed with fungus gnats to me.