refractometer ?

[daytonaconnecti]

i just used my new refractometer today, sg is 0.26, this also matches my friends refracto, my two swing arm hydro meters both read 0.23, they are different brands of swing arm meters,i cant beleve that they would both be off....that much..

 

[NaH2O]

Its amazing isn't it?

 

[mungus]

Swing arm hydrometers aren't that accurate. I know mine was off even more than that. Swing arm read 1.025 refractometer 1.030. Makes ya glad you spent the extra money!!!

Brian

 

[Blazer88]

Mine ended up being the same between my refrac. and hydrometer.....????

 

[chris&barb]

make sure you calibrate the refractometer with a salt solution not just ro/di

if you take one level 1/4 cup of morton's salt + one level teaspoon, then take a 2l coke bottle and fill it all the way to the top with ro/di, then mix the salt and water in a bucket or large pot. then match the temp of this mix to your tank water. this mix will be between 1.026 and 1.027 or right at 35ppt.

when i first got my refractometer i just used ro/di and it worked fine but when i recalibrated it with this mix i found that it was reading low,1.026 was really 1.024

 

[Blazer88]

Is there a solution I can order or something? Seems like that would be more precise than my trying to mix up my own.

 

[daytonaconnecti]

i thought you just use distilled water, it should read 0

 

[chris&barb]

Is there a solution I can order or something? Seems like that would be more precise than my trying to mix up my own.

if you have a good scale then you can way it out, but that mix is pretty accurate.

this artical talks more about it

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

 

[chris&barb]

i thought you just use distilled water, it should read 0

if you bought a really high end refractometer (more then $100-$200) then calibrate it the way they say. but for the less expensive hobby ones like what i have and most others then this is the way to go. if you were testing water that you wanted to have 0sg then i would calibrate it with Distilled water, but were testing salt water, and most people try to keep it at NSW levels so it only make sense to calibrate your refractometer with a standard that is at NSW levels.

 

[daytonaconnecti]

this is wat i was talking about ck it out http://diyreef.com/calibration.htm

 

[chris&barb]

that would be good if you were going to be testing something with an SG of close to 0. the standard that i posted is 1.026-1.027 or you could say 1.0265. if you used that and set it to that then you would be much closer. the article i linked talks more about why and how a refractometer works

 

[daytonaconnecti]

not to sound dumb, but iam confused, to witch cal method to use, wouldnt you want to zero it out, with a netural solution, then get the proper reading of sg.... rather then set it to a set sg you are using, then read it with your water...i was just thinking,if you could set a tire gauge to 32psi, and your tires need to be 32psi i guess it would eaither read higher or lower or on the money, in sted of using a gauge that reads 0 to 32 psi iam sure iam confusing you and my self...

 

[chris&barb]

it has to do with if the instrument was made correctly, and what it was made for. these less expensive refractometers that we are using are made for a broad range of applications. there used for beer and wine making for example. if your unit has a flaw and you calibrate it with ro/di to 1.0000 how do you know that its going to be correct when you are going to be testing salt water with a value of 1.0265? depending on what that flaw is your reading could be high or low by X, but if you take a known standard of 1.0265 and calibrate it with that, then when you test your tank water(and if you target for your tank is 1.0265) you know its right on. your bypassing the possible flaw.

why don't you test it. celebrate it with ro/di to 1.0000 then double check it with the standard. if it reads 1.0265 then your good to go. if it doesnt then you know your refractometer is off, and one little twist of the screw will fix it and you will never need to worry about it again.

 

[daytonaconnecti]

thanks i will try that....

 

[NaH2O]

Bill - do you know which refractometer you have?

 

[daytonaconnecti]

hey nikki, its the blue rhs-10atc that premium aqutics sales, btw how was the turnout? sorry i misses it, it was so close to me...

 

[NaH2O]

That's a good refract...I have the same, too. Here is a link to a recent thread about them: Randy's Refractometer Calibration Summary. Most refractometers are off by 0.0015 SG or 1.5 ppt out of the box, however, this one is correct, so no need to make adjustments.

Turnout was pretty good, and had a blast giving my presentation and socializing . Hopefully you can make it to the Feb meeting!

 

[Krish]

I sent you a pm, but here is some info I got for your from Premium Aquatics...

The refractometer should have come with a tiny screwdriver and there is a screw right behind the plastic lens cover that he will need to turn. You will need to use "Fresh RO" water to put on the lens and then look through the refract. itself and turn the screw until you get a reading of 0. He will see a line at the bottom where zero is and that is where he will need to calibrate it to. After that he will be able to put saltwater on it and it will read the salinity.

HTH

 

[daytonaconnecti]

cool this is what nikki, has posted... http://www.reeffrontiers.com/forums/showthread.php?t=10341

 

[snobanker]

Thats the exact refractometer that I bought. I just got it in the mail Saturday. I've only been putting it off for 2 years. I haven't had a chance to calibrate it yet but I am in a few minutes. I'm "kinda" looking forward to see far off my ol' swingarm hydrometer was off.

By the way just as an FYI. Dr Fosters and Smith has a special on these refractometers right now. http://www.drsfostersmith.com/Product/Prod_Display.cfm?pcatid=9957&N=2004+113761