@Dana Riddle did you notice effects from rain storms on tide pools? Seems like that would have to drop a tide pool's salinity like a rock.
I know Sustainable Aquatics has a white paper where they say they looked at fish and salinity and they apparently don't seem disturbed much at all by swings.
I made salinity measurements in some tide pools hat were isolated from the ocean at times. See here:
https://www.advancedaquarist.com/2009/6/aafeature
With that said, there had to be instances where tide pool salinity was under the influence of torrential rainfall and greatly affected.
I'll take a close look at these when I get a chance:
Coles, S.L. and P.L. Jokiel, 1978. Synergistic effects of temperature, salinity and light on the hermatypic
Montipora verrucosa. Mar. Biol., 48: 187-195.
Coles, S.L., 1993. Experimental comparison of salinity tolerances of reef corals from the Arabian Gulf and Hawaii. Evidence for hyperhaline adaptation. Proc. 7th Int. Coral Reef Symp., Guam. 1: 227-234.
Glazebrock, J.S. and R. Van Woesik, 1993. Effects of low salinity on the tissues of hard corals
Acropora spp.
Pocillopora sp. and
Seriatopora sp. from the great keppel region. Proc. 7th Int. Coral Reef Symp., Guam. 1: 307.
Nakano, Y., K. Yamazato and S. Iso, 1993. Responses of Okinawan reef-building corals to experimental high salinity. Proc. 7th Int. Coral Reef Symp., Guam. I:308
Nystrom, M., F. Moberg, and M. Tedengren, 1997. Natural and anthropogenic disturbance on reef corals in the inner Gulf of Thailand; physiological effects of reduced salinity, copper and siltation. Proc. 8th Int. Coral Reef Symp., Panama. 2: 1893-1898.