Refractometer calibration

[Recife]

Reposting the same question I posted on the newbie forum.

I got a refractometer from marine depot yesterday after using a hydrometer for over 2 months, which always showed 1.025.

The refractometer is showing 1.030! I'm scared, but before I go crazy on reducing the salinity, I want to make sure it's calibrated properly.

What's an easy way of doing that? There are no instructions in the box.

By the way, the tank looks extremely healthy.

[TwistedTiger]

<a href=showthread.php?s=&postid=7422401#post7422401 target=_blank>Originally posted</a> by Recife
I There are no instructions in the box.
Pull all of the foam out of the box sometimes they hide the instructions under there.

[Recife]

Someone else suggested that too.
I will take a look when I get home later. Thanks.

[brians_224]

I got one of those back at christmas time. Is it the blue 'more affordable' one?

If it is...check this out: http://reefcentral.com/forums/showthread.php?s=&threadid=733111

I had the same problem with mine. MAde the solution as per randy and verified against two fellow reefers tanks.

Good Luck.

[stevenb]

Place two drops of RO water on prizim wait 1 minute. Ajust so that the blue line is at zero.

[Randy Holmes-Farley]

If it reads 0 ppt in RO/DI, it is likely calibrated as per the directions. I also suggest testing it at least once in water matching NSW:

Reef Aquarium Salinity: Homemade Calibration Standards
http://reefkeeping.com/issues/2004-06/rhf/index.htm

[Recife]

Thanks all for the links.

Pardon my ignorance, but where can I get Morton's Iodized Salt?

[brians_224]

The grocery store.
Its the salt you likely use on your dinner table or in cooking.

[Recife]

Thanks for embarrassing me :-)

So how come there are two salt types listed in the recipe?

[javatech]

http://diyreef.com/shop/product_info.php?cPath=70&products_id=72

[Randy Holmes-Farley]

There is only 1 salt in the recipe. It is listed twice because there are two different types of measurements in most recipes (cups and teaspoons, typically).

[Recife]

I used the recipe to calibrate the refractometer last night.

Result? My salinity is 1.025 as opposed to the 1.030 I got initially.

Thanks all for the help!

[Randy Holmes-Farley]

:thumbsup:

Happy Reefing. :)