High salinity = sps death?

[Reefhaven]

i have been dealing with sps death for a while now and couldn’t figure why. All my parameters are with in range..alk 8.3, cal 468, mag 1500, nitrate 2-5, phosphate .03 but 1.030! I didn’t know until I decided to bring my tank water to my lfs and have them double check. I have been testing out 1.026 with my refractometer this whole time but it seems that my calibration solution is off. Sps tips would start to die and base with go too. Hoping this is the issue to all this death. Otherwise I don’t know what else is causing this.

 

[NY_Caveman]

Ugh. Sorry to hear. Sounds like you have a hold of it at least. You have some nice SPS so I hope some made it.

 

[Randy Holmes-Farley Verified Community Expert]

I would not assume that the salinity was the problem. Many SPS corals grow fine in the Red Sea, and the average salinity in it is about sg = 1.030.

That said, keeping it at 35 ppt (sg = 1.0264) or so sounds like a better plan.

 

[housemouse]

I would not assume that the salinity was the problem. Many SPS corals grow fine in the Red Sea, and the average salinity in it is about sg = 1.030.

That said, keeping it at 35 ppt (sg = 1.0264) or so sounds like a better plan.

I noticed that one of my LFSs keep sg = 1.030, measured with Milwaukee, and calibrated same day. They have some incredible mother colonies the size of bowling balls next to encrusted mounted frags. I'm almost tempted to slowly adjust my salinity to match my fav LFS.

What do you keep yours at, @Randy Holmes-Farley ?

 

[Randy Holmes-Farley Verified Community Expert]

I aim for 35 ppt, specific gravity = 1.0264

 

[Anxur]

I would not assume that the salinity was the problem. Many SPS corals grow fine in the Red Sea, and the average salinity in it is about sg = 1.030.

That said, keeping it at 35 ppt (sg = 1.0264) or so sounds like a better plan.

35 ppt (1.026) is not only the average, its the rule -- there is little variation. Like most Cnidarians corals have little osmoregulatory ability and in nature primarily exist in areas where the salinity fluctuates very little. When they encounter salinity changes in nature (heavy rains) it often kills large patches of the reef. In areas with consistently different salinity (e.g. the Persian Gulf), only a small number of corals are able to exist (a couple dozen species at best, compared to hundreds on the GBR).

I'm always surprised that people keep their reef tanks at anything but 35 ppt. I know it can be done (although inaccuracies in refractometer calibration make it unclear how often this is really the case), but why?

my $0.02