Ideal Salinity reading?

[cjj14u]

I see that most members here are keeping salinity in the 1.025 to 1.027 range.
The setup instrauctions that came with my Red Sea Max said to set it at 1.021 at 77 fegrees F.
Also my hydrometer shows the target range to be between 1.020 and 1.023.
Just wondering?
My tank is currently cycling with LS and LR.
Thanks.

[Michael]

1.021 is too low, if your only keeping fish then you could get away with it, but id suggest 1.026 or 35 parts to keep the water as close to nsw as possible, after all marine fish do live in the sea. i dont know what red sea are thinking about suggesting a lower level.

[rjwilcox]

bump your salinity up to 1.024 to 1.026. some say its better to have a lower salinity because it helps the fish with diseases. normal sea water is 1.025 so i would keep it there. i ran my tank at low levels and when i brought it up to 1.024-1.025 everything seems to be healthier.

[thegrun]

...and you would be well served to replace the hydrometer with a refractometer. Hydrometers are notoriously unreliable, do yourself a favor and get a refractometer.

[Randy Holmes-Farley]

I discuss salinity here:

The “How To” Guide to Reef Aquarium Chemistry for Beginners, Part 1: The Salt Water Itself
http://reefkeeping.com/issues/2007-03/rhf/index.php

from it:

What Salinity to Use?
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. Salinity, however, does vary substantially from place to place.

As far as I know, little real evidence suggests that keeping a coral reef aquarium at anything other than natural salinity 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. Substantial misunderstandings also arise among aquarists as to how specific gravity really relates to salinity, especially considering temperature effects.

The salinity on natural reefs has been discussed in previous articles. 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 salinity of 35 ppt (specific gravity = 1.0264; conductivity = 53 mS/cm).

Fortunately, coral reef aquaria seem rather forgiving with respect to salinity. The range of salinities encountered in what most would proclaim as successful reef aquaria is actually quite large. Don’t agonize over small deviations from natural seawater. You will not notice any benefit changing from 36 or 34 ppt to 35 ppt (specific gravity = 1.0256 to 1.0271). Many fine reef aquaria appear to run at salinity levels as low as 31 ppt (specific gravity = 1.023), but bear in mind that the values that aquarists report (as well as your own measurements) are fairly likely to be inaccurate, so pushing the low or high end of the range may not be prudent.

Bear in mind that if aquarists target salinity values different than 35 ppt, the amounts of calcium, magnesium, alkalinity, etc., will all likely deviate from natural levels as well. For example, making artificial seawater to a low salinity will normally result in low values for these parameters and may require adjustments.

[Michael]

great post randy thanks for that, i think your absolutely right as well, surely it has got to be sensible to keep all marine animals and fish at nsw levels, i dont understand why red sea would suggest a lower level.

[Randy Holmes-Farley]

Thanks, Michael. :)

Happy Reefing!

[redsea reefer]

I discuss salinity here:

The “How To” Guide to Reef Aquarium Chemistry for Beginners, Part 1: The Salt Water Itself
http://reefkeeping.com/issues/2007-03/rhf/index.php

from it:

What Salinity to Use?
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. Salinity, however, does vary substantially from place to place.

As far as I know, little real evidence suggests that keeping a coral reef aquarium at anything other than natural salinity 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. Substantial misunderstandings also arise among aquarists as to how specific gravity really relates to salinity, especially considering temperature effects.

The salinity on natural reefs has been discussed in previous articles. 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 salinity of 35 ppt (specific gravity = 1.0264; conductivity = 53 mS/cm).

Fortunately, coral reef aquaria seem rather forgiving with respect to salinity. The range of salinities encountered in what most would proclaim as successful reef aquaria is actually quite large. Don’t agonize over small deviations from natural seawater. You will not notice any benefit changing from 36 or 34 ppt to 35 ppt (specific gravity = 1.0256 to 1.0271). Many fine reef aquaria appear to run at salinity levels as low as 31 ppt (specific gravity = 1.023), but bear in mind that the values that aquarists report (as well as your own measurements) are fairly likely to be inaccurate, so pushing the low or high end of the range may not be prudent.

Bear in mind that if aquarists target salinity values different than 35 ppt, the amounts of calcium, magnesium, alkalinity, etc., will all likely deviate from natural levels as well. For example, making artificial seawater to a low salinity will normally result in low values for these parameters and may require adjustments.

yeah, what he said...:)

[cjj14u]

great post randy thanks for that, i think your absolutely right as well, surely it has got to be sensible to keep all marine animals and fish at nsw levels, i dont understand why red sea would suggest a lower level.

Thanks for the responses!! I am gradually "bumping it up" as we speak...

I double checked just to be sure and yes, the Red Sea startup guide states:

"A salinity of 30.6 ppt, i.e a specific gravity of 1.021 at 25 deg. C / 77 deg. F is recommended for most saltwater aquariums".....

Go figure...

Thanks again!!!

[cloak]

I've kind of thrown the numbers out the window. As long as I can line the water level up to the bottom of the green part on my $6.99 floating glass hydrometer, everything is fine.

[Zebodog]

Salinity or SG will also affect other levels in the tank, i.e. Calcium.

I like a SG 1.025

[coastie81]

salinity is 35ppt, 1.025 is specific gravity.