# Just a question.



## AshleytheGreat (Jul 24, 2005)

Alritgh I dont have a SW tank but this has always bothered me.

I read that -- 1 cup salt/5 Gall willl rasie the SG to .005
(Got that info form wetwebmedia.com)
>>If I wanted the SG to be 1.025 would I add 5cups/5gALL?
Math   
1c/5g = .005
2c/5g = .010
3c/5g = .015
4c/5g = .020
5c/5g = .025

Now...would I need to keep adding more Instant O. or is freshwater already at 1.000? lol

Oh and another thing...
I also read that the temperature makes the SG different so if I was to do a water change...would I have to wait till the bucket of new water is the same temp of the tank to add the salt OR could I add what I normally would and have the water reach the tank heat, in the tank?


Haha...Thanks, Ash


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## TheOldSalt (Jan 28, 2005)

It doesn't work out in practice the way it should in theory, but your salt ratio formula is pretty close to correct. Try 4 cups to 5 gallons and then test with a hydrometer to see how it winds up once fully mixed.

Fresh water is indeed 1.000.

The temperature difference is very significant. It is important that you get the temperature right before measuring in order to get the correct reading. If you use an expensive refractometer this isn't a problem, but with a hydrometer it is. Those big lab grade hydrometers are usually calibrated at 59F, but most aquarium models are calibrated at 76F. if you can measure at 76 you'll get the most accurate reading, but you'd only be off by a very insignificant bit if you tested anywhere in the mid 70's.


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