What is the IDEAL specific gravity for corals?

kellenr

kellenr

Member
I know everyone has their own opinions on what the SG/Salinity should be in a tank but I'd like to know what is best from 'personal experiences'. The reason I'm asking is because I used to have my SG @ 1.024 and some people told me they'd bring it down to around 1.020 because it's easier for the fish to breathe. Even some guys at my LFS's said some of their tanks are at 1.019.
I took that into consideration and dropped mine down a few notches to see if I could notice any difference. I think the lowest I went was 1.020 and I noticed my soft corals weren't looking so well. I left it there for a few weeks until recently when I brought it up to 1.025 and my corals/anemones seem to be opening much more and look fuller and healthier (there's a huge difference). I haven't noticed any affects on my fish either way.
I've read in multiple places that corals prefer a SG ranging from 1.024-1.026. Wouldn't you think the fish would be fine in that environment as well? Does it really impact their breathing that much to make a difference? And what other pros/cons are there in having a higher SG?
So my question is: What is the most 'ideal' specific gravity for a tank with soft corals and fish?
(NOTE: I'm talking about a reef tank with corals, anemones, inverts, LR & fish. I'm not really concerned about FOWLR systems).
 
M

markeo99

Guest
coral needs higher salt levels and fish only tanks can run low levels cause it wards off some parsites that cannot tolerate low salinity and no offence
get a refractometer best investment I ever made cause there are 2 many variables with specific gravity temp prob even altitude but a refrac 35 ppt
 
scsinet

scsinet

Active Member
Originally Posted by KellenR
http:///forum/post/2647204
The reason I'm asking is because I used to have my SG @ 1.024 and some people told me they'd bring it down to around 1.020 because it's easier for the fish to breathe. Even some guys at my LFS's said some of their tanks are at 1.019.
Wow.
There are reasons for running lower salinity, but "easier to breathe" is a new one. It saves money on salt when operating very large fish only systems, and it helps reduce proliferation of disease because marine invertebrates cannot survive on lower salinity.
Marine organism's natural environment is 1.024 - 1.026 or so. It varies depending on where in the world you are, temperature, all kinds of factors. It is NOT stable across the world, but 1.020 is not natural.
I took that into consideration and dropped mine down a few notches to see if I could notice any difference. I think the lowest I went was 1.020 and I noticed my soft corals weren't looking so well. I left it there for a few weeks until recently when I brought it up to 1.025 and my corals/anemones seem to be opening much more and look fuller and healthier (there's a huge difference). I haven't noticed any affects on my fish either way.
This is because corals are not tolerant of salinity levels that low. Fish are much more tolerant, they can survive 1.010 for weeks at a time.
I've read in multiple places that corals prefer a SG ranging from 1.024-1.026. Wouldn't you think the fish would be fine in that environment as well?
Yes.
Does it really impact their breathing that much to make a difference?
No.
And what other pros/cons are there in having a higher SG?
Apart from what I said above, none really. If you have corals or invertebrates, you must maintain 1.024 - 1.026 for the long term survival of your corals and inverts. Much below this and things begin dying quickly.
So my question is: What is the most 'ideal' specific gravity for a tank with soft corals and fish?
IMO 1.025.
 
reefkprz

reefkprz

Active Member
I run all my tanks at 1.027 but thats because I have zero fluctuation and use my water as my only dosing so for trace element maintinence reasons I run a higher specific gravity.
osmoregulation for fish becomes more energy consumiong at higher salinities. running lower salinities is easier for fish to osmoregulate (think about this ->, balance salt content of body, versus surrounding water) at higher salinioties it becomes more taxing on the fish, cost more energy, so sick fish tend to show disease easier because they expend X amount of energy just regulating bodily processes that they cant devote to boosting their immune system. this is most prevalent in new tanks and newly aquired fish. stress factor if you will.
 
kellenr

kellenr

Member
Ok well I'm glad that my intuition held true. I thought my tank environment operated best at 1.025 or so. Now after seeing the results of lowering the salinity (and all of your opinions to confirm) I feel that what I was doing all along was probably best suited. I already had made up my mind to maintain the higher salinity when I saw how quickly my corals improved. I mean you can literally see them open fuller within hours of adjusting salinity from low to high. I'm going to go ahead and keep my tank at 1.025, I didn't see a reason it needed to be lowered anyway.
Now let me ask this, does algae grow more prominently at lower or higher salinity levels?
 
stanlalee

stanlalee

Active Member
Originally Posted by SCSInet
http:///forum/post/2647214
Wow.
There are reasons for running lower salinity, but "easier to breathe" is a new one.
according to scott michaels reef fishes "at lower salinity fish have to expend less metabolic energy to conserve water in their body tissues."
he also stated having sality at sea level for fish is pretty much not neccessary. For example studies of the emporer angel showed it survived long term with no signs of stress at 7ppt with no problems and the lethal limit was 5ppts. On the other hand salinity a small amount above see level causes dehydration.
 
bang guy

bang guy

Moderator
Originally Posted by KellenR
http:///forum/post/2647204
So my question is: What is the most 'ideal' specific gravity for a tank with soft corals and fish?
Whatever combination of Temperature and S.G. gets you to a salinity of 35ppt - 37ppt.
 
al mc

al mc

Active Member
Originally Posted by Stanlalee
http:///forum/post/2647507
according to scott michaels reef fishes "at lower salinity fish have to expend less metabolic energy to conserve water in their body tissues."
he also stated having sality at sea level for fish is pretty much not neccessary. For example studies of the emporer angel showed it survived long term with no signs of stress at 7ppt with no problems and the lethal limit was 5ppts. On the other hand salinity a small amount above see level causes dehydration.

Originally Posted by reefkprZ
http:///forum/post/2647527
thats osmoregulation.
This is why it is very safe to use hyposalinity on fish. Many have argued that the hyposalinity state is harmful or stressful to fish. That would be incorrect since they do expend less energy in the hyposalinity state than in a 'reef safe' SG of 1.026.
As for original poster question about corals. Reefkeeper and Bang Guy have more experience than I, but I run my reefs at 1.026 SG and 78-80 degrees.
 
scsinet

scsinet

Active Member
Originally Posted by Stanlalee
http:///forum/post/2647507
according to scott michaels reef fishes "at lower salinity fish have to expend less metabolic energy to conserve water in their body tissues."
he also stated having sality at sea level for fish is pretty much not neccessary. For example studies of the emporer angel showed it survived long term with no signs of stress at 7ppt with no problems and the lethal limit was 5ppts. On the other hand salinity a small amount above see level causes dehydration.

This is all true, however he has corals so the whole concept of lower salinity is out the window.
FO systems can be run much lower, in fact, I ran my FO system at 1.020 until I decided to add a couple sea urchins.
 
stanlalee

stanlalee

Active Member
Originally Posted by SCSInet
http:///forum/post/2648237
This is all true, however he has corals so the whole concept of lower salinity is out the window.
FO systems can be run much lower, in fact, I ran my FO system at 1.020 until I decided to add a couple sea urchins.
correct. I know he cant use lower salinity I was trying to address what his pet store told him "lower salinity makes the fish breath easier".
 
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