Ideal Salinity
- Thread starter drcole
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1.024-1.026 has always worked well for me.
I'm sure there have been times over the years where the SG was a little higher or lower than this, but nothing bad ever seemed to happen. Maybe a little pouting, but that was about it.
I'm sure there have been times over the years where the SG was a little higher or lower than this, but nothing bad ever seemed to happen. Maybe a little pouting, but that was about it.
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Randy Holmes-Farley
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https://www.reef2reef.com/threads/o...-reef-aquarium-by-randy-holmes-farley.173563/
Salinity
There are a variety of different ways to measure and report salinity, including conductivity probes, refractometers, and hydrometers. They typically report values for specific gravity (which has no units) or salinity (in units of ppt or parts per thousand, roughly corresponding to the number of grams of dry salt in 1 kg of the water), although conductivity (in units of mS/cm, milliSiemens per centimeter) is sometimes used.
Somewhat surprisingly, aquarists do not always use units that naturally follow from their measurement technique (specific gravity for hydrometers, refractive index for refractometers, and conductivity for conductivity probes) but rather use the units interchangeably.
For reference, natural ocean water has an average salinity of about 35 ppt, corresponding to a specific gravity of about 1.0264 and a conductivity of 53 mS/cm. It often ranges from 34-36 ppt over reefs, but can be higher or lower locally for various reasons such as land run off of fresh water, or evaporation from a lagoon.
As far as I know, there is little real evidence that keeping a coral reef aquarium at anything other than natural levels is preferable. It appears to be common practice to keep marine fish, and in many cases reef aquaria, at somewhat lower than natural salinity levels. This practice stems, at least in part, from the belief that fish are less stressed at reduced salinity. I have no idea if that is true or not, but I've not seen evidence that it is true. Substantial misunderstandings have also arisen in the past among aquarists as to how specific gravity really relates to salinity and density, especially considering temperature effects. For example, the density of seawater is less than the specific gravity, and measurements with glass hydrometers may require temperature correction, but newer devices do not need the aquarist to make corrections. Consequently, older salinity or "specific gravity" recommendations may not actually be referring to the same measurements that aquarists make today, even if the recommended numbers have been handed down
My recommendation is to maintain salinity at a natural level. If the organisms in the aquarium are from brackish environments with lower salinity, or from the Red Sea with higher salinity, selecting something other than 35 ppt may make good sense. Otherwise, I suggest targeting a target salinity of 35 ppt (specific gravity = 1.0264; conductivity = 53 mS/cm).
Salinity
There are a variety of different ways to measure and report salinity, including conductivity probes, refractometers, and hydrometers. They typically report values for specific gravity (which has no units) or salinity (in units of ppt or parts per thousand, roughly corresponding to the number of grams of dry salt in 1 kg of the water), although conductivity (in units of mS/cm, milliSiemens per centimeter) is sometimes used.
Somewhat surprisingly, aquarists do not always use units that naturally follow from their measurement technique (specific gravity for hydrometers, refractive index for refractometers, and conductivity for conductivity probes) but rather use the units interchangeably.
For reference, natural ocean water has an average salinity of about 35 ppt, corresponding to a specific gravity of about 1.0264 and a conductivity of 53 mS/cm. It often ranges from 34-36 ppt over reefs, but can be higher or lower locally for various reasons such as land run off of fresh water, or evaporation from a lagoon.
As far as I know, there is little real evidence that keeping a coral reef aquarium at anything other than natural levels is preferable. It appears to be common practice to keep marine fish, and in many cases reef aquaria, at somewhat lower than natural salinity levels. This practice stems, at least in part, from the belief that fish are less stressed at reduced salinity. I have no idea if that is true or not, but I've not seen evidence that it is true. Substantial misunderstandings have also arisen in the past among aquarists as to how specific gravity really relates to salinity and density, especially considering temperature effects. For example, the density of seawater is less than the specific gravity, and measurements with glass hydrometers may require temperature correction, but newer devices do not need the aquarist to make corrections. Consequently, older salinity or "specific gravity" recommendations may not actually be referring to the same measurements that aquarists make today, even if the recommended numbers have been handed down
My recommendation is to maintain salinity at a natural level. If the organisms in the aquarium are from brackish environments with lower salinity, or from the Red Sea with higher salinity, selecting something other than 35 ppt may make good sense. Otherwise, I suggest targeting a target salinity of 35 ppt (specific gravity = 1.0264; conductivity = 53 mS/cm).
NY_Caveman
likes words, fish and arbitrary statistics
LOL. I just re-read this last night and was about to post it. Picked up a Pinpoint Salinity Monitor and was making a new calibration solution. I had previously made the one for my refractometer. Works like a charm!
The goal is to become a mixed reef, I have some changes coming when I move in October but would like to get some of the kinks worked out. Would it be appropriate to top off with saltwater in order to raise the salinity??
A properly calibrated refractometer is probably your best bet, but I prefer a floating glass hydrometer. No muss, no fuss.
NY_Caveman
likes words, fish and arbitrary statistics
I have used hydrometers, refractometers and now have the salinity probe which measures conductivity. This probe is by far the best.
Hydrometers are iffy and cannot be calibrated (except for doing the math to make adjustments). I find they degrade over time and must be kept clean.
The refractometer has worked well for me, but I find it must be calibrated every time I take it out. I also have always had difficulty seeing through eyepieces (microscopes, binoculars, etc.).
Using conductivity, which is new to me, is very easy and it holds its calibration well. I can leave the probe in the saltwater and add top off water and watch to reach an exact number without constant retesting.
Randy’s article above is excellent for learning the differences and making calibration solutions.
Hydrometers are iffy and cannot be calibrated (except for doing the math to make adjustments). I find they degrade over time and must be kept clean.
The refractometer has worked well for me, but I find it must be calibrated every time I take it out. I also have always had difficulty seeing through eyepieces (microscopes, binoculars, etc.).
Using conductivity, which is new to me, is very easy and it holds its calibration well. I can leave the probe in the saltwater and add top off water and watch to reach an exact number without constant retesting.
Randy’s article above is excellent for learning the differences and making calibration solutions.
NY_Caveman
likes words, fish and arbitrary statistics
Sorry, Randy’s link was a different article. I meant this one which is also excellent:
http://reefkeeping.com/issues/2004-06/rhf/index.htm
http://reefkeeping.com/issues/2004-06/rhf/index.htm
NY_Caveman
likes words, fish and arbitrary statistics
I used a hydrometer years ago. For my return to reefing i picked up an AquaMaxx refractometer. I like it but I recalibrate every use. I just picked up a used Pinpoint Salinity Monitor and i am loving it. Whatever you choose, calibrate and test.
chipmunkofdoom2
Always Making Something
I can second this. I bought my Pinpoint almost 2 years ago and it has been great. I test the calibration monthly and I just last month had to adjust it. It was only off by 0.2 mS/cm, which is pretty incredible seeing as how I use it almost daily and I haven't had to touch the calibration in almost 2 years.
Conductivity meters are a bit pricey, but after using one I'll never go back to a refractometer, digital or handheld.
fnlyreefready
Active Member
I think mine is at .27 rn we’ll confirmed. And yeah the nems are pouting a little bit you San see they are obviously in decent health still
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reefsaver
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I try to stay at 1.025 or 33.5 PPT because at around 35PPT my Anthelia starts wilting. I personally believe slightly elevated salinity in conjunction with slightly elevated alkalinity and calcium contributes to faster growth.
Randy Holmes-Farley
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Sounds odd. I've never heard of any marine organism suffering at 35 ppt salinity. How are you measuring salinity?
I'm not sure I understand the context of the last sentence. Certainly, it is well established that higher alk and pH boosts the skeletal growth rate of some hard corals. I'm not sure that higher salinity without higher alk does so.
reefsaver
Well-Known Member
I just imagine all the nutrients and trace elements in the salt are more concentrated as the salinity increases, in conjunction with higher alk.
And yeah I'm not quite sure it was the salinity, I did a water change, changed out the carbon, dipped the anthelia and moved it to a different spot in the tank.
I think it may have been a low flow issue as it was placed in an area that's been gathering a brown surface algae on the sand. I don't know if it's related but I've noticed my skimmer's filling up with foam and bubbling over before filling with liquid which's a first for me. I recently changed my Aquascape and removed a single 30kg piece of texas holy rock which I think is the actual cause.
I use a Hanna Salinity Tester "the wand thingy"
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Derrick0580
Valuable Member
I try and shoot for 1.026 as that is natural sea water salinity.
TastyScrants
Active Member
I aim for 35ppt.
I’ve started using the Hannah salinity checker with monthly calibration. I like this because I travel a lot for work so my girlfriend can easily use this to check while I’m away.
Having a much better experience than with a refractometer, however the refractometer I was using was low quality and didn’t have temperature correction.
I’ve started using the Hannah salinity checker with monthly calibration. I like this because I travel a lot for work so my girlfriend can easily use this to check while I’m away.
Having a much better experience than with a refractometer, however the refractometer I was using was low quality and didn’t have temperature correction.
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