balashark21
Member
and will it go up or down with warmth?? i cant figure it out from my early post
what is the perfect specific gravity for saltwater???
- Thread starter balashark21
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krishj39
Active Member
Well, there is a range. My opinion is 1.025 if you have corals, 1.023 if it's just fish. Temperature will change the reading on a hydrometer, but the hydrometer will say somewhere what temperature it is calibrated for. I still use a hydrometer, but if it is really important to you, you should get a refractometer as it is far more accurate and doesn't need to be at a certain temperature.
sammystingray
Active Member
balashark21.......you know how things get less dense when hot because the molecules are excited and moving fast? Well, that is why specific gravity is effected.....you are not really measuring the salinity when using a hydrometer....this is why they are quite inaccurate....it is more a density issue. When the water is hot and less dense....any floating device or swing arm device will sink more because the water is less dense, but the plastic arms density stays the same.....if the water is cold and more dense.......the arm of the hydrometer still stays the same, but it is now less dense compared to the water, and so it floats higher and gives a higher reading. Maybe I didn't answer your question.....I was just trying to explain why temp effects floating devices used to check salinity.....I think most plastic swing arm type hydros are set at 76 or something......anyone know? you need to adjust for each degree of temp to get an accurate reading...I have seen charts, but I don't have one handy....sorry.
D
daniel411
Guest
... you all use salt? Uh oh...
