Specific Gravity

spider9376

Member
I'm trying to set up a reef tank and I need to know what would be the best SG to stay at? Right now it is at 1.026, Temp is 77.3 0 Ammonia 0 Nitrate 0 Nitrite P/H 8.4. My tank is a 55Gal and I think I have about 30 lbs of liverock. My tank has been running sents May 3rd. 2008. My live stock are
1 small percula Clown, 1 Small Clown Tang 2 Pajama Cardinal, 2 pepperment shrimp, 2 Featherduster, 3 Anemones, 1 Orangespotted Slepper Goby, 3 small emeral crabs, Finger coral, and a a family of Polyps. any help?
Thanks Spider9376
 

fatcat

Member
1.026 is spot on, are you testing with a hydrometer or a refractometer??
And that tang is going to out grow your tank in know time i'd sell it or take it to the LFS for store credit..
That tang need aleast a 120Gal..
 

candycane

Active Member
Where are you? The higher the altitude, the more pressure that is on the tank. Since I am in Colorado, I keep it lower.
 

spider9376

Member
I really don't know. what is the differance between a hydrometer and a refractometer. The one I have I dip it into the water up to a line and it gives me the reading. I did not know about the tang needing a 120Gal tank, I just bought him on the 29 of Sept 2008 and the girl said it would do good in my tank!!!! So you are saying that having the Clown Tang in a 55Gal tank is like me living in my bathroom all the time?
Thanks Spider9376
 

candycane

Active Member
Well then yours should probably be on the higher end - like 1.025-1.026, since you are right about at sea level.
Refractometers are sometimes more precise. With hydrometers there is a decent amount of room for error even if a tiny bubble is stuck to the needle. A bubble could even get stuck to one of the glass floating ones and it would raise what it says that SG is at.
 

aztec reef

Active Member
your off by three digets...
1.026 on a hydrometer = 1.029 on a refractometer( which is most accurate)..
 

spider9376

Member
Well now I know I dont have refractometer, but I will get one, How do you use it? Do you dip it into the water and then read it? I know I have a hydrometer now that you have told me the differance.
Thanks Spider9376
 

candycane

Active Member
There is usually a calibration fluid and a drop of water needs to be placed on the end. Then you look through the eyepiece and see where it levels out to. It's like a horizontal microscope almost.
You can buy MONITORS that just sit in the tank and the display just hangs somewhere. They work like digital thermometers.
 

bang guy

Moderator
Originally Posted by Aztec Reef
http:///forum/post/2786000
your off by three digets...
1.026 on a hydrometer = 1.029 on a refractometer( which is most accurate)..
Can you explain this for me?
IMO a conductivity meter is slightly more accurate than a refractometer but not significantly for our purposes.
 

bang guy

Moderator
Originally Posted by Spider9376
http:///forum/post/2786016
Well now I know I dont have refractometer, but I will get one, How do you use it? Do you dip it into the water and then read it? I know I have a hydrometer now that you have told me the differance.
Thanks Spider9376
A refractometer is used by placing a couple/few drops of tank water on a glass lens and using light. It will show how much the light bends as it passes through the water (refractive index). Refractive index can be correlated to Salinity by looking through the refractometer at the scale. It cannot measure Specific Gravity.
 

aztec reef

Active Member
well i don't think we're talking about an EC meter, we're talking about a dipping, non-electrical condutivity meter vs. a refractometer..
which i have tested , and it always results in 3 degress difference vs. a refractometer..
Ec meters and tds meters are without a doubt the accurest testing devices.
or i'm wrong?
 

candycane

Active Member
Originally Posted by Aztec Reef
http:///forum/post/2786067
well i don't think we're talking about an EC meter, we're talking about a dipping, non-electrical condutivity meter vs. a refractometer..
which i have tested , and it always results in 3 degress difference vs. a refractometer..
Ec meters and tds meters are without a doubt the accurest testing devices.
or i'm wrong?
What?
 

aztec reef

Active Member
never mind it helps to read post # 4 throughout.. lol
"The one I have I dip it into the water up to a line and it gives me the reading"
 
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