Got a refractometer and WOW, way out...gotta fix

[Slick Fork]

I ordered it from J&L so I would hope that it's one meant for the aquarium trade! I did calibrate it with the "ultra pure" water that came with it. Is that alright or should I locate some of this pinpoint 53 stuff?

[Okguy]

I would confirm the refractometer readings first before making changes. Take a water sample to you're local store (if there is one around) and have them confirm the readings. If the livestock doesn't appear to be stressed with your current water parameters, you might as well take your time and make sure the changes are required.

I once made slight changes because a new thermometer I bought was faulty and the consequences were pretty severe. Just better to be safe than sorry.

[Slick Fork]

Unfortunately there's no LFS around that deal in SW stuff. Closest would be Calgary and that's a 2hr drive for me. Are there any other ways I could confirm the reading? Livestock isn't visibly stressed at all so I'm not in a panic, it'll just bug me now that I know about it!

[Reefer Rob]

Stability is more important than the actual level. A reading of 1.030 on the refractometers they sell at J & L is probably about right, as they read high. They also sell the 53 uS calibration fluid.

For more info read this thread

[ron101]

If the readings are accurate and you want to drop from 1.030 to 1.024 you will need to swap out about 25 gallons total (assuming total volume of 125gal) - more if you are doing it incrementally.

If you use RO water you will probably have to supplement more calcium and carbonate additives to keep overall levels up.

[midgetwaiter]

You can make your own calibration solution by following the info in this article:

http://reefkeeping.com/issues/2004-06/rhf/index.htm

You really want to do it with a scale though and make sure you get the solution right. The AMI calibration solution is cheap enough that I wouldn't bother.

My refractometer was pretty good at first but it has been off more and more lately, probably dropped it or something. I was just lucky enough to have heard about the potential problems with the calibration already so I didn't go and screw anything up. If your livestock looks good make sure you can confirm your measurement before you change something.

*EDIT*

I don't like the coke bottle thing in the article and I had a few minutes to kill so I figured out how to make up a decent solution if you don't have a scale but do have a fairly precise liquid volume measure. You need to mix 3tsp table salt in 491ml RO water. Assuming that the tsp of salt measures 6.2g, it should be pretty close, that will give you a solution that should read 35 ppt or 1.265ish.

Turns out the calibration I did to my RHS10-ATC based on a Deep Six hydrometer reading was bang on. Back to the drawer with the refractometer.

[crystalz]

I also started with a hydrometer. Hydrometers shouldn't even be sold as a salt/sg measuring device. My refractometer was a real eye opener for me too. Hydrometer was way out.