Why would one want to do such a thing? Corals are osmoconformers.
Their little "slap in the cellular face" has a word. Osmotic Shock. We purposely try to mimic 35 ppt salinity to avoid osmotic shock so why would you do it on purpose. Sure, you will see an increase in cellular activity by...
I've seen it stated a number of times. This is one that I found real quick.
"Low tides can be a problem for corals and can lead to mass mortality, especially if they coincide with heavy rains. Corals are used to stable ocean salinities and a sudden change to fresh water can be fatal.
However...
It's interesting to me that during low tide, these corals can be quite fine. However, if it happens to rain during low tide, they often die. They can handle massive UV, massive heat, but can't tolerate freshwater hitting them. Go figure.