No, low
Ca won't hurt the Nudi but it will affect the health of univalves as well as other
CaCO3 consuming organisms. It can also make
alk hard to control.
pH should be preferabley averaging 8.1-8.3 but depending on the time of day tested 7.8 (early AM) to 8.5 (late PM) is quite common. Salinity should be closer tp
NSW values 35
ppt (1.027
SG) & temps in the range of 78-80°.
Cheers
Steve