So my refractometer was off...

[bosscrab]

Salinity is 1.022. How slowly should I bring it up to .025?

[Fly Guy]

Just top off with saltwater instead of freshwater is a very safe way to bring it back up.

How did you find out out of curiousity?? I get a kick out of how everyone says refractometers are so much more accurate than hydrometers, yet i dont think many people have their refractometers calibrated properly

[bosscrab]

Well I got both. Just for S&G I used the hydrometer... off. So I went to the LFS( didn't get out w/out buying something) and they had same reading as my hydrometer. Good rule to keep that thing calibrated.
It's not like I keep it in a toolbox, but it was off.

[Hop]

Fly Guy: Very true. I would still have been off if I had not read a post about it... Pretty easy to do as long as you know how to calibrate it

For those that don't know, calibrating them to 0 w/ RO will only get you in the ball park. You need to use a calibration solution or a homemade stock solution to calibrate them accurately. I was .04 off.

[bosscrab]

What kind of homemade solution? Got a link?

[Hop]

Somewhere It may take a while for me to find it... it was a long time ago, but was something Holmes-Farley supported.

[Fly Guy]

http://www.marinedepot.com/md_viewIt...product=AM1437


I have seen the homemade one.........but it either looked like too much of a PITA, or i gave up thinking so after reading several paragraphs....one of the two

[Hop]

OK it's definately easier to buy the premade calibration fluid But here is a formula for making a stock solution...

189.42 grams of table salt into 5 liters (5,000 ml) of water will give you exactly 35ppm or 1.0264 sg at 77 degrees F. You can do the math to make a smaller stock solution, but I read this is the easiest to measure out so that your not trying to mix 27.87464637438949484578 ml of water

Here is a linkyhttp://www.reefkeeping.com/issues/2004-06/rhf/index.php

[Fly Guy]

Thats easier than the solution i saw....i think it is anyway. Or i used to give up way easier than i do now

Or maybe it was Tom who explained it and it was information overload

[Hop]

Dunno, I'm not even going to try. I would have to calibrate my scale in order to calibrate my refractomter. So in essence the blind leading the blind in my little world I'll stick to the premade solution and hope for the best

[bosscrab]

Originally Posted by Hop

Dunno, I'm not even going to try. I would have to calibrate my scale in order to calibrate my refractomter. So in essence the blind leading the blind in my little world I'll stick to the premade solution and hope for the best

Might be the best way to go. I'm no chemist.

[leveldrummer]

my refractometer says to use distilled water, how acurate would that be? would it be better than ro/di??

[Hop]

According to what I read... No. You would still be much better off calibrating with the solution as it zeros the refractometer at 1.026 @77 degrees.

Mine said distilled water also, but I was told that the RO would work as well. Unfortunately, I guess that may have been an issue

[Fly Guy]

Originally Posted by leveldrummer

my refractometer says to use distilled water, how acurate would that be? would it be better than ro/di??

so do mine. The first one i checked was off .002 from the calibration fluid vs distilled. the newest refracto i bought i didnt check the difference just used the fluid

i dont know if it would be better than ro/di. For $5 i suggest just buying the fluid and knowing for sure

[Fly Guy]

ROTFL @ Hop. I was typing too slow