Salinity question

MAKOOKAM · 11/10/2009, 08:30 PM

Where do you guys keep your reef salinity and why? I have been keeping mine at 22 but i've been hearing of others at 25, 26. What is considered optimal?

JonnyD91 · 11/10/2009, 08:41 PM

I believe a salt mix at 25 or 26 will give higher levels of DKH and calcium. I like to keep mine between 26-27

greenbean36191 · 11/11/2009, 07:32 AM

Well if you're talking about actual salinity, it should be about 35 psu. That's the average for full-strength seawater worldwide. Reefs range from about 34-42 psu.

If you mean specific gravity, then 35 psu corresponds to about 1.0265.

Somewhere within about 0.002 of that is generally considered ideal because that's what our animals evolved in.

Despite the myth in the hobby, there is little to no disease resistance conferred by keeping the salinity slightly lower and doing so can be stressful and even damaging to the gills, kidneys, intestines, and livers of fish.

Randy Holmes-Farley · 11/11/2009, 07:41 AM

I agree.

This has more:

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:

http://reefkeeping.com/issues/2007-03/rhf/index.php#13

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.

Toly · 11/11/2009, 08:47 AM

A lot of times ppl lower salinity to lower costs, ie less salt used, etc. I would bet many LFS do that, at least for fish.

11/10/2009, 08:41 PM	#2
JonnyD91 Registered Member Join Date: Jan 2005 Location: Manalapan NJ Posts: 1,444	I believe a salt mix at 25 or 26 will give higher levels of DKH and calcium. I like to keep mine between 26-27 __________________ Click my super cool username dropdown menu to see my new 90 Gallon In wall Build on my user home page :) Current Tank Info: 90G Reef - 2 MP40's - Apex Controlled - Reef Octopus PRO-SSS-DC1 Skimmer - 6 Bulb ATI Sunpower

11/11/2009, 07:32 AM	#3
greenbean36191 Premium Member Join Date: Jun 2003 Location: Ft. Lauderdale Posts: 10,598	Well if you're talking about actual salinity, it should be about 35 psu. That's the average for full-strength seawater worldwide. Reefs range from about 34-42 psu. If you mean specific gravity, then 35 psu corresponds to about 1.0265. Somewhere within about 0.002 of that is generally considered ideal because that's what our animals evolved in. Despite the myth in the hobby, there is little to no disease resistance conferred by keeping the salinity slightly lower and doing so can be stressful and even damaging to the gills, kidneys, intestines, and livers of fish. __________________ Some say the sun rises in the East. Some say it rises in the West. The truth must be somewhere in the middle. Current Tank Info: tore them down to move and haven't had the time or money to set them back up

11/11/2009, 07:41 AM	#4
Randy Holmes-Farley Reef Chemist Join Date: Apr 2001 Location: Arlington, Massachusetts Posts: 86,233	I agree. This has more: 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: http://reefkeeping.com/issues/2007-03/rhf/index.php#13 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. __________________ Randy Holmes-Farley Current Tank Info: 120 mixed reef

11/10/2009, 08:30 PM	#1
MAKOOKAM Registered Member Join Date: Sep 2009 Posts: 26	Salinity question Where do you guys keep your reef salinity and why? I have been keeping mine at 22 but i've been hearing of others at 25, 26. What is considered optimal?

11/11/2009, 08:47 AM	#5
Toly Registered Member Join Date: Dec 2008 Location: NY Posts: 85	A lot of times ppl lower salinity to lower costs, ie less salt used, etc. I would bet many LFS do that, at least for fish.