When is the last time you calibrated your refractometer??

[Jan]

I was reading on another forum about problems people were having with their corals, and it turned out that their salinity was out of whack, because their refractometers had gone out of calibration.

So, since I'd bought some Pinpoint calibration fluid recently I decided to test my refractometer with it.

It was off by .04, reading 1.030 instead of the 1.026 that it should have.

After calibrating the refractometer and testing my tank water, I see that my water is only 1.018, not the 1.022 I thought it was!

This is not good. How quickly should I bring it up and not shock the corals? Are we talking about replacing my RODI topoff with SW, or an immediate water change?

 

[CarlaW]

Thanx for the reminder, you can calibrate it with distilled too, can't you?

 

[Scooterman]

Actually I check mine frequently because a have a lots of 53mS fluid LOL.
Distilled will make it slightly off, I just compared it a few days ago!

Jan, I'd raise it up to 35ppt, I don't go by sg (correction) with a refract. just doesn't serve the purpose when you can measure both! 35ppt is approximately 1.0265 sg BTW!

I would do it slowly, adding slightly higher sg during a wc is a good slow way to bump it up.

 

[Jan]

I've read not to use distilled or RODI, but I know plenty of people do that anyway. I'm not enough of an expert to explain why or why not.

 

[Jan]

Jan, I'd raise it up to 35ppt, I don't go by salinity with a refract. just doesn't serve the purpose when you can measure both!

Scooty, do you mean that I should use a swing arm hydrometer to measure instead of a refractometer? Or how do you measure it if not using a refractometer?

 

[Scooterman]

Jan better yet read this!
http://www.reeffrontiers.com/forums/showthread.php?t=30998

Charlie read this!
http://www.reeffrontiers.com/forums/showthread.php?t=20893

 

[Scooterman]

Scooty, do you mean that I should use a swing arm hydrometer to measure instead of a refractometer? Or how do you measure it if not using a refractometer?

No, your refract. should have both measurements in it, 35ppt & across that should be 1.0265 sg (aprox)
Swing arms aren't that reliable but I do use it to get my new salt mix up & test it quickly after it is up to Temp. then I use the refract to get it just right!
I actually have a formula now when I do a 25g wc, I can get real close just by counting cups of salt mix.

Sorry I meant SG, not salinity my bad!

 

[NC2WA]

Jan,

I check mine (and calibrate if necessary) once a month.

 

[Kurt_Nelson]

Thanx for the reminder, you can calibrate it with distilled too, can't you?

That will set zero, but you should also use the 53 mS calibration fluid Scooterman mentions. It should read 35 ppt on your refractometer. One data point doesn't make for a true calibration - you need two.

 

[Jan]

I cross-checked mine tonight with a swing arm hydrometer and unfortunately, I think it really is 1.018. Water change tomorrow morning. But I could use some advice on how high salinity to use in the makeup water...I don't want to shock the corals or fish.

 

[mmn_usn]

I test mine about once a month with the refractometer and weekly with the swing arm... and they match most of the time if not all...

 

[Scooterman]

I cross-checked mine tonight with a swing arm hydrometer and unfortunately, I think it really is 1.018. Water change tomorrow morning. But I could use some advice on how high salinity to use in the makeup water...I don't want to shock the corals or fish.

Jan, post #6 I put up the link for you to read on how to do that safely, reading from the real experts is up-most important in this hobby due to lots of hearsay, opinions etc that goes on as it does so much these days.

 

[Jan]

thankyou, Scooty. At first I read the wrong thread (intended for Charlie). The Boomer post and Salinity Adjustment calculator is exactly what I needed.

 

[trido]

Thanks for calibrating my refractometer Jan. Its the first hting I did when I got home from the meeting. Thankfully my salinity was only 1.024 I'll raise it up regardless..

 

[treehugger]

Maybe it's time I actually get a refractometer...Duane/Jan maybe one of you could bring yours by sometime so I can see what I actually run at... not that it really matters as long as it's consistently the same on whatever you're measuring it with and your corals are happy

 

[Scooterman]

Maybe it's time I actually get a refractometer...Duane/Jan maybe one of you could bring yours by sometime so I can see what I actually run at... not that it really matters as long as it's consistently the same on whatever you're measuring it with and your corals are happy

Actually it matters more that you think, If your too far one way or the other could impact your corals in ways your not seeing & critters like snails & shrimp big time etc.

 

[Jan]

I'll bring my refractometer when I come over today, Jeff.

 

[cwegescheide]

I know Randy Holmes Farley has a DIY 1.026 salinity solution to check your refracto with using table salt and a 2 liter bottle full of water. I did it and worked like a charm.

 

[Kurt_Nelson]

And here's the link, if anyone's interested...

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

I tried it and didn't trust my measurements for the salt and liquid. You have to be pretty darn precise. Glad I just spent the $5 or whatever for some Pinpoint solution.

 

[Jan]

hey folks, an update on my salinity saga.

After getting an unusually high Ca reading on a newly mixed batch of SW, I pulled out a new salinity measurement tool that I hadn't used before: the large Tropic Marin floating hydrometer, touted to be accurate to .001 (at temp of 77 degrees). Well, this hydrometer measured my salinity at 3.5 points higher than both of my calibrated refractometer and my cheap swing-arm hydrometer (which read the same as oneanother).

Now what?? This is starting to make me crazy. :|