Can a drop of 1ppt salinity affect acropora?

[The Opinionated Reefer]

I have noticed some of my acros have started to lose color at the tips and even stn. I have recently switched to a calcium reactor and my alk has not been perfectly stable but never more than a 1dkh swing from where is supposed to be which is 8.5dhk. I have been focusing so much on alk that somehow my salinity has crept down from 35ppt to 34ppt I am assuming this would also have had effects on alk? I am bringing it back up by adding salt water to my ATO but is surprising how much is need to increase by 1ppt in a 350L tank. So far I have only managed to increase by 0.1.

I am wondering if this is likely the cause of the stn or if it could be a delayed reaction to a minor alk swing when my calcium reactor stopped dosing over night once or a combination of both.

 

[vetteguy53081]

Unless it was instantaneous, likely not however a drop or increase in ph, alk or nitrates would.
Something to check
Also look for presence of any little bugs or nudibranch

 

[The Opinionated Reefer]

my ph goes up and down like yoyo every night and it has never had any negative effects. It can change as much as 7.8 to 8.3 in one day depending on the light cycle. I dose nitrates just to get a reading. They are sitting around 10 just now and phosphate 0.1

 

[coralbeauties]

Is your stn happening overnight or at no time in particular. Seems that if I have an stn event with a coral it seems to happen overnight. I always suspect it to be a drop in ph overnight which is always the lowest ph time of the day. I agree with @vetteguy53081 that lower salinity wont cause any quick issues. I have caught myself with as low as 32ppt with not much issues other then corals not looking the best.
jeff

 

[Charlie’s Frags]

I’ve never had any issues with minor salinity swings. My alk swings all over the place and still don’t have any issues, but I keep my no3/po4 much higher than most. I feel the alk swing issues happens to hobbyists with low nutrients.