Refractometer

[Tswifty]

Anyone have a portable refractometer lying around they would be willing to sell?

Let me know. Thanks.

 

[cloakerpoked]

Been a while since we've seen you around

 

[Tswifty]

Yeah I was in Texas for a week, and have been pretty busy since I've gotten back.

 

[cloakerpoked]

That guy with the sump for sale had a refractometer I think...but he was trying to sell it with everything else.

 

[Tswifty]

Thanks, I saw that. I found one locally that I think is going to work though.

 

[acer]

I picked up Frakb1's bag of goodies- yes there is a refractometer in it. So I have two. I have not checked it out yet - busy day - I will sell one of mine- dont need two. Pm me or call - I think you have my number

 

[cloakerpoked]

PM me a price, I may be interested...

 

[acer]

still in my car- will check out tomorrow

 

[acer]

ok i now have two portable refractometers. They do NOT, repeat do not agree on the salinity of any water sample. Model RHS-10ATC . Does anybody know how to "make" a sample- that is of a known value? so I can calibrate them.

 

[raynist]

I think you are supposed to use DI water and calibrate them to 0.

I may have some calibration fluid. I think I got some from salty critter. I will take a look.

 

[raynist]

ok, I have some salinity solution. It says it is 53.0 ms solution. Not sure what that is in ppt though. Anyone know?

 

[raynist]

Just found it. The solution is 35ppt.

 

[acer]

ray can you bring some to work this week- will purchase it- I found a thread here on R/C that says that 35 ppt is exactly the solution i need to calibrate the refractometers with . Thanks ( as usual you save the day)

 

[Tswifty]

Yes 35 ppt (Salinity) is equivalent to 1.0264 (Specific Gravity).

 

[acer]

ok - got the 35 ppt solution from Ray - thanks Ray. Will calibrate today and then test. Hopefully they both will work.

 

[cloakerpoked]

Seeing as that our tanks will change anyway through a range, and successful tanks are kept anywhere between 1.021 and 1.028, how important is it that we have the precision of a refractometer as opposed to simple hydrometers that will come close (+- .003) enough to keep it within that range?

 

[Bowman]

<a href=showthread.php?s=&postid=15112399#post15112399 target=_blank>Originally posted</a> by cloakerpoked
Seeing as that our tanks will change anyway through a range, and successful tanks are kept anywhere between 1.021 and 1.028, how important is it that we have the precision of a refractometer as opposed to simple hydrometers that will come close (+- .003) enough to keep it within that range?

Just my .02 but I have yet to find a hydrometer with that kind of accuracy. Hydrometers are usally all over the place so you don't know what your salinity is really at.

 

[cloakerpoked]

<a href=showthread.php?s=&postid=15112438#post15112438 target=_blank>Originally posted</a> by Bowman
Just my .02 but I have yet to find a hydrometer with that kind of accuracy. Hydrometers are usally all over the place so you don't know what your salinity is really at.

Not to start an argument, but I have 6 from different tank purchases (just not something you can sell) and have checked against 2 others, and they all fall in a pretty reasonable range. I've never had one read 1.015 and one read 1.030. As a matter of fact, they all fell in that range that I mentioned before. (+- .003). This doesn't make them right, but they should be as consistent as a refractometer, and if you checked it against one, you should be able to come close enough to not have problems. I believe in having accurate tests, but salinity just isn't something that I'm as anal about I guess.

 

[Bowman]

No Argument at all. With the range of salinity you mentioned (1.021-1.028) and with the accuracy factor taken into consideration (+-.003) You would have a range of 1.018 to 1.031. If you don't know for sure what youre hydrometer reads than your salinity is just a shot in the dark. You are correct that if you test your hydrometer against a known salinity and make a note of the reading you can use it for a quick reference tool. IMO a refractometer is a cheap enough investment considering the total investment we have in our tanks. Steve Pro did a article comparing the accuracy of swing arm hydrometers compared to refractometers awhile back I believe. Cheers

 

[acer]

yes- that is why I purchased a used one to begin with. Also I always had difficulty getting all the air bubbles off the hydrometer arm.