What happens to the salt when water the evaporates?

[InfernoST]

Hi All
Hopefully this one will be a lot easier then the thread on lighting and wattage. When the water in the tank evaporates does the salinity increase? Is it me or does the specific gravity also increase when the tank gets cooler?

[ccCapt]

Yes, the salinity increases because the volume of water decreases. You have the same amount of salt in less water which equals a higher salinity.
Temp does have an affect on salinity, but there should not be such a big swing in temps in your tank to notice a change from temp.

[InfernoST]

Originally Posted by ccCapt

Yes, the salinity increases because the volume of water decreases. You have the same amount of salt in less water which equals a higher salinity.
Temp does have an affect on salinity, but there should not be such a big swing in temps in your tank to notice a change from temp.

Boy you sure get around Capt, I' glad you do. I noticed the change in the relationship between specific gravity and temp when I was adjusting my wacky heaters. If I find the need to top off I would just add treated straight water?

[Boulder]

Not to hijack, but I'm curious to know this as well ... whether to top off with RO water or will just a gallon jug of distilled water from the grocery store work for top off in a FOWLER.

[HN1]

For top offs, use pure RO. If you're using grocery store water, you're better off using the RODI from the machines instead of distilled plus it's even cheaper!

[melosu58]

Yes that Larry is the man. He hit it right on the nose.

Now to Boulder. Either will do. I topped my reef off with Food Lion distilled water for 7 yrs so that will work also IMO.