Temperature does play a role in getting an accurate reading on your salinity. I know that when I open a new bag or bucket of salt I always do a full specturm of tests on the change water to see where I am at as far as ph, calcium, alk., mag., phosphates, etc. By just dissolving salt in warm water I don't know how you would control how much you are raising your salinity. If mine were low I would use salt water as make up water for evaporation but still want to know what the salinity is and keep testing my display to see where I am at.

Well thanks for all the tips. Its always good to learn new things, so i am going to take what i learned today and try it out.

Yes, temperature is a factor on your SG readings.
If you are using a basic hydrometer there is a conversion to apply.
I looked online for a conversion table but could not find anything, within my patience tolerance.
If you can gain access to the book "Natural Reef Aquariums" by John H. Tullock (Revised Ed. January 2001), there is a hydrometer readings conversion table, as it relates to temperature, on page 121.

I suppose the refractometer is doing this conversion for you, but then can the refractometer detect the temperature of only a few drops of water?

At any rate, try to get your hands on, and check out, that book.

Cheers,

More accurately, what I mean to say is...you'd think that the temperature of a few drops of water would change, dramatically, as they are removed from the aquarium and I wonder how a refractometer could possibly take that into account.

But then, I have never used a refractometer and am not sure how they are employed. Do you just dip a probe into the tank water itself?

Cheers,

Refractometers are temperature compensated by their nature.... you put 3 drops of your aquarium water on the plate... wait 15 - 30 seconds... then look through they eye piece at a bright light... there you will see a scale of numbers where your salinity can be read... After comparing an AP and Coralife hydrometer to my Refractometer, I found the Coralife one to be out by <3ppt and the AP one to be out >1ppt... I STILL use these for daily visual checks as they are too easy to use... and just use the Refractometer for calibrations and precise readings.

Steve! I woulda thought YOU of all people would never do that! Right now I have an elegance that has been cranky for over a week now... why? Because I scraped my %$#@&&!! centre brace, and some salt creep broke off and snowed into the tank... so I AM speaking from experience on this one too... but just MY experience... I guess some people get away with some things... :mrgreen:

Oh ya... one more for Steve...

"The aforementioned posts are strictly the opinion of the author and in no way are representative of broadly accepted or expert opinions on the subject matter. The author does not assume responsibility nor liability for improper use of said information as he may or may not have been on drugs at the time of writing"

PRACTICE SAFE SEX EVERYONE! :mrgreen:

So, a refractometer isn't as easy to use as a hydrometer is?:question:
(Can't be too difficult, is it?)
(I'm thinkin' of gettin' one.)

Cheers,

That would just be an indication of my laziness.... While you can take a hydrometer, dip it and get an instant albeit somewhat inaccurate reading,... the refractometer requires removal from the case, dripping the water, reading, then cleaning off with RO/DI water before putting away... a process that all told takes 2 mintes instead of 10 seconds.... lol

I think that with the huge :wink: task of rinsing my hydrometer, both before and after, and looking up and applying the correction, they both sound equally as labour intensive. :rolleyes:
For the sake of the accurate readings they (refractometers) give, I'm gonna get one.
Do you use a pipette for the water drops with yours? I suppose that would have to be rinsed too! :rolleyes:

Cheers,

Oh ya! Ya gotta clean that too! What a chore I'm tellin' ya! I actually keep a gallon of pure water right beside the tanks just for rinsing various acoutrements necessary to the hobby....