SWF.com water - specific gravity on recent order off!!

[jamie814]

I just received my order from SWF.com (3 fire shrimp DOA) as I started temp acclimating everything I got out my refractometer for the heck of it checked the specific gravity of the water here’s what I got,
Bags with inverts 1.028

Bags with fish 1.018

Thought maybe my refractometer was off so I calibrated it with RO/DI water and it was at 0 so those reading are right :scared:
checked again still got the same reading in all the invert bags and the same in the 2 fish bags.
Now I keep my tank at 1.024 and those numbers seem kind of off and not so good for the specimens. Anyone else every checked their water when receiving orders or care to chime in on this???

 

[ophiura]

1.018 is not uncommon at all for fish. Be happy that they do not keep their inverts under the same condition as many others do.
As for the 1.028...I recommend people keep their systems at 1.025-1.026 for inverts. Inverts tolerate HIGH specific gravity relatively better than LOW specific gravity. I would be far less happy if the specific gravity came in at 1.022 - 1.023 than 1.028. I've never had issues with inverts received from SWF

 

[alyssia]

I've never tested the sg of the water I've got in my orders from swf, and I've never experienced a problem with anything, with the exception of one DOA which was replaced.

 

[bang guy]

FYI - Refratometers do not measure Specific Gravity.... they measure Salinity. 35ppt - 37ppt is acceptable for inverts in my opinion.

 

[oreo12]

Originally Posted by Bang Guy
FYI - Refratometers do not measure Specific Gravity.... they measure Salinity. 35ppt - 37ppt is acceptable for inverts in my opinion.
I think you are wrong mine has the specific gravity scale not a salinty scale. Maybe yours is difrent than mine I know they make refractometeres for many things you can even get one to test your anti freeze in your car.

 

[birdy]

What Bang Guy is saying is that Refractometers actually measure salinity not the specific gravity of saltwater, there is a SG level on the refractometer that correlates with the salinity level, but you should read the Salinity level on a refractometer.
And I most certainly second the opinion that those levels are perfectly acceptable for fish and inverts.
Another thing to consider is to actually check the refractometer against a salinity calibration. Perhaps your refractometer is not accurate (calibrating with DI water is not 100% accurate).

 

[ophiura]

Yeah, unfortunately there are a lot of factors as well. There is a temperature variable, there is a temperature for the DI water used to calibrate, etc etc. In the end, I don't think there is much concern over the levels.

 

[bang guy]

Originally Posted by oreo12
I think you are wrong mine has the specific gravity scale not a salinty scale. Maybe yours is difrent than mine I know they make refractometeres for many things you can even get one to test your anti freeze in your car.
You should have got one with a Salinity scale. Refractometers cannot measure water density except at one specific temperature.

 

[beth]

Originally Posted by Bang Guy
FYI - Refratometers do not measure Specific Gravity.... they measure Salinity. 35ppt - 37ppt is acceptable for inverts in my opinion.
Some measure both, such as the one I had.

 

[theappe]

I recently got one too and it has both

 

[bang guy]

Originally Posted by Beth
Some measure both, such as the one I had.
It may have a scale for both (mine does) but the S.G. scale is only there because somewhere along the road hobbiests began to think that S.G. is important. Salinity matters
The S.G. scale on a refractometer is almost always wrong. The Salinity scale on a calibrated Refractometer is very accurate.
If you think about how S.G. varies so much with temp and Salinity doesn't you can see how both scales just can't be accurate at the same time except at a specific temp (typically 67F).

 

[fishieness]

hey bang: then what is the purpose for one with ATC?

 

[bang guy]

Originally Posted by fishieness
hey bang: then what is the purpose for one with ATC?
ATC compensates for the refraction difference of a few degrees. Basically it will help to keep the refractometer accurate at normal reef temps.

 

[theappe]

Originally Posted by fishieness
hey bang: then what is the purpose for one with ATC?

atc = automatic temperature control (i think)
it adjusts to temperature

 

[fishieness]

Originally Posted by Bang Guy
ATC compensates for the refraction difference of a few degrees. Basically it will help to keep the refractometer accurate at normal reef temps.
see, i knew that, but you jsut said that temp still will swing it a lot? also, my refractometer had to be calibrated at 68 degrees F, whil my reef is between 78-80.... will it not work as planned then? Since it had ATC i had thought it would do that....

 

[bang guy]

Temp will affect S.G. a lot. It doesn't affect Salinity much.

 

[fishieness]

oh, yeah, im getting confused. But then it wouldnt matter if a refractometer had a scale for SG because it measures temp (which is what matters). So if 35-37 ppm is acceptible in salinity, but your refractometer says you have 1.025-1.026, then it wouldnt matter if it showed up in SG, because although it may not be the TRUE SG, it is measureing it according to what matters right?

 

[bang guy]

What matters is Salinity.
S.G. should only be referenced when using a hydrometer and then you need to adjust for temp.
Hydrometers measure water density. The fish & inverts could care less what the densit of the water is. Salinity affects them, not water density.
Hydrometers are a way to derive Salinity. Refractometers measure Salinity directly so there's no need for a temperature table to come up with 35 - 37ppt.

 

[fishieness]

hmmm.... i was confused to what you were saying, and i think i was confused when trying to type what i was asking, but im okay now. so lets just leave it at that.
thanks bunches for the replies and patience but what i was asking didnt make sence and i understand now. :happyfish

 

[dogstar]

Originally Posted by Bang Guy
Hydrometers measure water density. The fish & inverts could care less what the densit of the water is. Salinity affects them, not water density.
.
I agree the levels posted of SWF's water is not too dangerous....But I would not like to see those levels with anything that I would buy....
The way the S.G. thing is, I understand that higher " densities " can effect the metabolism of the fishes skin and keep it from maintianing/releasing liquids from the body properly. Higher S.G. can cause the fish to dehydrate over time. Lower S.G. is not as bad as with FO systems or short term hypo but too low for too long is not good.
S.G. should be watched in relationship to the temps. of a tank as well as salinity. You change the salinity by adding or removeing the ppms of minerals/salts in the water in order to adjust the S.G. that you want acording to the temps. of the tank.
IMO, they are both important......
Im not sure how the metabolism of inverts act. I would think with the many differant types, there could be different systems with them.