what are the effects of high salinity on sps?
 

Was hoping for some input or experience on this topic. Cheers.

How high are we talking? Iv had mine up to .031 by accident for a few weeks without any issue. Sps don't mind the high salinity, from my experiences its everything else in the tank that has a hard time with it.

I agree, SPS will be the last to notice the salinity. I recently just had mine drop low (1.017) because my refractometer was out of calibration ... and it was the fish that showed the first signs that something wasn't right ... I never would have noticed because my SPS were showing no signs of stress at all.

Really? I've had exactly the opposite experience. I went out of town for a week when my tank was about 5 months old. I didn't have the ATO system set up yet so I had the R/O float switch plumbed right in to the sump. When I left I set the skimmer cup to empty right to a sewer drain. Something in the tank made the skimmer go nuts while I was gone, and when I got home my specific gravity was 1.018. I think 4 corals out of 15 survived, fish were unfazed.

Too high will kill your fish first. I had mine at 31 one's and killed off one of my fish. SPS showed no problems at all.

Lower salinity is harder on corals than higher salinity.
Try to keep the salinity around 35 to 38 ppt.
Much variance beyond that and the coral will spend a lot of it's energy maintaining it's internal ionic balance.
If the coral spends too much energy maintaining that balance, it will die.

Thanks guys. Some of my corals were not looking as good and realized my salinity was 30

I think this is probably due to how fast your change took place. Your salinity dropped to 1.017 very quickly due to the skimmer malfunction, mine has dropped over the course of a year as my refractometer slowly went out of calibration over a long period of time.

I am now trying to bring it up equally slowly to prevent any issues with the tank. I am topping up with saltwater every other day to slowly increase the salinity without shocking anything.

Lojack, how did your refractometer drifting out of calibration cause your salinity to drop?
When you did water changes, did you add less salt to each batch?

I don't weigh or measure my salt. I have two 80 Gallon Drums, one for fresh RO, and one for Saltwater.

My RO unit fills the freshwater drum and runs off of a float, and it's connected to the drum I use for saltwater, I open the valve and fill the other. I just add salt to the drum, and test the salinity to get it where I want it. Weighing and mixing a set amount of salt with a set amount of water is inconsistent because the batches of salt are rarely on spec and exactly the same.

I was calibrating my refractometer with Distilled water as per the instructions that came with it, then I stumbled across a really good article that was talking about how distilled water and RO water for calibration can cause refractometers to drift. So I bought some Calibration solution that is exactly set to 1.026 concentration and found that my Refractometer was indeed off, by .008 which is fairly substantial in the grand scheme of things.

I intend to add a conductivity probe to my Apex to prevent this problem in the future ... however right now I'm still checking salinity the old fashioned way.

Actually, measuring salt water mixes by weight is the more accurate, measuring by specific gravity is less so, because for sg readings it depends on what temperature the water is.
I understand now how your refractometer could have messed things up.
Your refractometer should say in it's viewing window what temperature it was calibrated to at the factory.
Can I ask what calibration fluid you used, also which article you read regarding the difference between distilled and R/O?

I could see weight being accurate, however I wouldn't weigh it, it would be more of a 6 cups of salt makes this much water etc etc ... except my drum isn't filled to the same spot everytime, and measuring would never be exact (at least in my circumstances). Even if I had a fill line on the tank ... I wouldn't know the exact volume and so on haha.

My question about weight though would be this. Considering if I test Bucket A of my salt after mixed to 1.026, from lot 996 and I get 450 Calcium and 11 dKh and then I test Bucket B of my salt from lot 997 and get 470 calcium and 13 dKh ... would weight truly be accurate. Would the added minerals not offset the amount of NaCl in the solution?

I use Instant Ocean, but I've also seen lots of threads where people test their mixed up saltwater from different buckets of all sorts of brands and have varied parameters.

As for the article ... All I remember is someone posted a link to it on ReefCentral. It was a .uk link though, if that helps narrow it down.

Sorry if I keep pushing on this, but your claim of your corals showing no stress, after a year of lowering salinity down to 1.017 surprises me. I'm wondering if you are getting accurate results even now. Corals need a certain balance of ions in order to process their life functions, so they would have had to take in extra fluid in order to compensate for the lower available ions in the water column.
You have a great looking tank and I would hate to see it suffer for a preventable reason.

The only calibration solutions I've seen are ones that you use for a probe, which you have to warm up to 25C, or ones that are stated to be 35ppt, that you can use on a refractometer.
Having a calibration fluid at 1.026 without stating at what temperature, leaves a critical bit of information out.

Other than a bit of faded purple on my bonsai ... I have no signs of stress on my tank. I just posted a recent full tank shot and everything seems to be doing great.

The solution I bought is a Pinpoint Marine solution from Reef Supplies. It says right on the bottle 1.026, 53.0 mS, and 35 ppt. Thats what I used to recalibrate the refractometer. And I had it at close to 25c because I keep the room warm as opposed to running multiple heaters in my little fishroom.

You may be right, the salinity may or may not be as low as it is. For all I know, the calibration solution isn't spot on ... tough to tell for sure. I have a hydrometer thats worth about $100 that floats. It's glass and bobs in the water and indicates your level. I don't use it because you have to kill all your flow and pumps to get an accurate reading, but perhaps I will break it out to try and see how far off the refratometer actually is.

I would guess that the 1.026 number is for 25C, but your refractometer is calibrated for 20C, which would mean the reading is still off.
Next time you use your refractometer, see if the scale in the viewing window has a 20C or 20/20 symbol. That would confirm it.

Some refractometer scales in the window have a conversion number right beside it. If yours does, see if it's in the ppt measurement.
If so, get your refractometer instrument to 20C and use that same calibration fluid, but calibrate to 35 ppt.

I agree, it looks great. I watch my corals to see if anything is wrong, then I use testing equipment to pinpoint what it is.
By the looks of your tank, very little, if anything is out of whack.
- so I hope you're not fixing a problem that doesn't exist.:smile:

Amen to that, me neither lol