i understand this problem perfectly from different point.. when i grow weed, the younglings are most vulnerable to ph changes (absorbtion balance of minerals, nutrients..) oh and balance of bacteria in medium aswell. Point is, tap water without letting it sit is enough to mess up the balance, and you notice the difference. growth might be hindered or the plant dies alltogether.. Ph is everything.

anyway, id imagine sea life being even more directly vulnerable since there is no medium (buffer) in between.