salinty

[mike007]

Wow i just received my new refractometer today and calibrated it . I have been using a swing arm hydro. now for years. After testing with the new toy my salinty was 1.030 with the swing arm 1.024. What a shock.

 

[always reefin]

no surprise...lol

 

[Breakin Newz]

refractometer FTW!

 

[Downbeach]

Good move. What are you using to calibrate it with? If it's just RO water, I'd get some solution that will calibrate it at/near where you want the sample solutions to test at, i.e. 35ppt.
Here's an example:
Aquarium Testing Solution: American Marine Inc. 53.0 mS Calibration/Reference Fluid

 

[mike007]

I just used di water. Looks like i will have to bring down salinty slowly.

 

[kuansreef]

I only use digital refractometer, very easy to use. Just press and show.

 

[Mike J.]

I've got a refractometer and it reads the same as my hydrometer that I've been using for years.

 

[dwilliams87]

+1 on the calibration solution. It can make a difference of .001-.002 which is enough to cause problems if you like to run at one end or the other.

 

[A-SpecUA6]

So I should get rid of my Red Sea Hydrometer cuz my salinity can be off the charts?

 

[mike007]

After my experience yes refracter for sure.

 

[Battlecorals Verified Sponsor]

Be aware of a bad batch of sybon 35 ppm cal solution. It reads much lower than it should. Caused a headache for me a little while ago.

Here is the batch#R1G01320


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[bct15]

I just used di water. Looks like i will have to bring down salinty slowly.

Be careful because you calibrated at 0 salinity so that is where you are accurate and your bias error exponentially increases as you get away from your calibration point.


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[mike007]

I don't understand what you mean.

 

[Downbeach]

I don't understand what you mean.

See "Slope Miscalibration" in this article:

Refractometers and Salinity Measurement by Randy Holmes-Farley - Reefkeeping.com

 

[bigkai]

Well after reading this last night I got to thanking (hey iv been setting my refractaometer with ro water). So this morning I get out my meter and test my tank its dead on 1.025. I test my ro water it reads 0. That I get out my cailibration fluid and it test 1.022. =-O

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[shellynjason]

I love using the refractmeter too. My instructions said to calibrate with ro/di and so I did, then after reading this site almost everyone suggested to use a calibration solution to calibrate it. So I bought the solution and it calibrated exactly to the ro/di water ... so atleast I have a peice of mind that it truly is calibrated correctly. My 'swing arm' was only off about .01, sounds like yours was way off though.