Salinity question
- Thread starter Shimis
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WVNed
The fish are staring at me with hungry eyes.
https://www.reef2reef.com/threads/o...-reef-aquarium-by-randy-holmes-farley.173563/
From there
"
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)."
From there
"
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)."
Flippers4pups
Fins up since 1993
I've always kept mine at 1.026 or 35ppt.
Montiman
Valuable Member
For fish systems a lower specific gravity is common for for main reasons.
1. It is way cheaper
2. Many believe a lower salinity prevents disease outbreaks.
In public Aquarium’s where a lot of our formal data comes from the difference between 1.026 and 1.020 could mean 10s of thousands of dollars saved every year. I have not been to a public aquarium that kept their salinity above 1.021.
When you visit wholesalers or many old school fish keepers you may find salinity even lower. When I worked at an old school LFS my boss had us keep the salinity at 1.017. He was convinced that this would limit disease even though it is mild for a true hyposalinity treatment. I have since found many service companies who are so worried about disease in their clients tanks that they run them all below 1.020 for years.
For a home reef aquarium always run natural sea water levels of 1.025 to 1.026. Frankly I wish public aquariums and those stubborn service companies would too because the low salinity tanks always seem to get fish with washed out colors and HLLE. As a temporary disease prevention low salinity may be valid.
1. It is way cheaper
2. Many believe a lower salinity prevents disease outbreaks.
In public Aquarium’s where a lot of our formal data comes from the difference between 1.026 and 1.020 could mean 10s of thousands of dollars saved every year. I have not been to a public aquarium that kept their salinity above 1.021.
When you visit wholesalers or many old school fish keepers you may find salinity even lower. When I worked at an old school LFS my boss had us keep the salinity at 1.017. He was convinced that this would limit disease even though it is mild for a true hyposalinity treatment. I have since found many service companies who are so worried about disease in their clients tanks that they run them all below 1.020 for years.
For a home reef aquarium always run natural sea water levels of 1.025 to 1.026. Frankly I wish public aquariums and those stubborn service companies would too because the low salinity tanks always seem to get fish with washed out colors and HLLE. As a temporary disease prevention low salinity may be valid.
Flippers4pups
Fins up since 1993
It’s anecdotal about lower SG preventing parasite spreading. It may slow them down to some degree, thus some hobbyists do this in QT/hospital tanks, but doesn’t stop them completely. So it’s a moot point to me. As for coral tanks it’s hard on coral growth and health.
U
User1
Guest
My opinion is no one really knows what is best. Why? Because the fish and corals can't talk to us. On the other hand, we as hobbyist, can share how our reefs are kept and at least use that as a reference or starting point. Then let the tank guide us as to what actually works and what they like. This doesn't mean have it going all over the place but if you use 1.026 or 35ppt as your baseline at least you know what you started with. No different than what your other water parameters are. A known baseline.
That is at least how I run and there are a couple corals in my tank that let me know, without signs or communication, how angry they are when mine are above their norm.
That is at least how I run and there are a couple corals in my tank that let me know, without signs or communication, how angry they are when mine are above their norm.
ScottR
Surfing....
I keep mine at 1.026 because it’s always worked so no need to change. But also, when I bring in corals from a LFS or a friend, their salinity is always at 1.026 so acclimation isn’t needed. I saw someone said that they saw no evidence of fish being less stressed at higher salinity as we’ve seen suggested. I too agree with that. I’ve never seen a fish look stressed in my tanks or others tanks. They seemed perfectly perky to me.
vetteguy53081
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My preferred range is 1.024-1.026
