Really high salinity slowing coral growth?

[Randy Holmes-Farley Verified Community Expert]

What do you mean by contamination? I can't think of anything other than adding significant percentage of RO water or tap water to calibration fluid (why would one do that, anyway?)

Anything getting in with a lower salinity than seawater, such as ro/di water. No one would do it intentionally, but it might get in by, say, using a pipette that one thought was empty but actually had water already in it.