Originally Posted by
mkroher
http:///forum/post/3085225
I just want to say that evaporation does not affect the salinity THAT much.
My Story....
I have a 29gal, and I wanted to perform hyposalinity.
Replacing approximately 5 gallons of saltwater with freshwater only dropped the SG about .002! And I measured the water at 20 minute, 1hr, and 2hr intervals.
I did a 3-5gallon water change in the morning, and one in the evening. It took a week to get the SG down to 1.009.
So in my opinion.... if you lose a gallon due to evaporation, there's no need to sound the alarm and freak out if you're not there to top it off.
Try it for yourself. Measure SG before and after top-offs. And if your eyeball can see a difference in the refractometer, then you have the eyesight of a hawk.. congrats.
So there's my two cents. Take it or leave it. No reason to fear the SG-police.
-Mike
I have done this and you are correct. It didn't change much at all. With this case is topping off with saltwater will bring it up over time.