ro/di water and refractometers!!!

[DevilBoy]

What people say about not using ro/di water to calibrate a refractometer is true. I was at my LFS and bought a bottle of pinpoint salinity monitor 53 ms calibration solution. I checked it with my refractometer and it read 1.031.... Whoa!!! so i calibrated it to this solution to read 1.026 then checked my tank water and it read 1.020... Holy toledo!!! i guess this explains why some of my SPS are looking like crapola!!! So please buy this $3 bottle of solution and check your refractometer with it. Especially if you calibrate it to read 0 using ro/di water... your meter will be off.

[Randy Holmes-Farley]

:thumbsup:

I'm glad you found the method useful. :)

[DevilBoy]

Thanks Randy... i think i seen the info about it in one of your articles that i read.


Would you think this could be the reason why my SPS are not doing well?

[jtma508]

Then on the other hand... initially I didn't have any standard with which to calibrate my refractometer. I set it against RO/DI water and the sailinity of my new tank was measured at 1.026. The following day I went to my LFS and got some standard solution and found that the refractometer was dead-on. I checked against the RO/DI water and nothing had changed.

[DevilBoy]

well i guess you are one of the lucky ones... it has taken my sps frags to look like crap for me to check the refractometer... but i am glad i calibrated it now

[Randy Holmes-Farley]

Would you think this could be the reason why my SPS are not doing well?

I think that is unlikely. :)

[DevilBoy]

<a href=showthread.php?s=&postid=12779188#post12779188 target=_blank>Originally posted</a> by Randy Holmes-Farley
Would you think this could be the reason why my SPS are not doing well?

I think that is unlikely. :)


I dont know what else it could be all water parameters test out great.

Ammonia 0 ppm
Nitrite 0 ppm
Nitrate 0 ppm
pH 8.0 - 8.2
Temp 77 - 80
Ca 425 ppm
Alk 8 dKH
mag 1400 ppm
salinity 1.021 but getting it up to 1.026

[Toddrtrex]

Randy, why is it that some people see this much of a difference, where as myself found that there was no difference b/t using RO/DI set to 0, or the solution set to 35 PPT?

[DevilBoy]

Todd it could be the brand of refractometer that is being used also....

[Toddrtrex]

<a href=showthread.php?s=&postid=12779556#post12779556 target=_blank>Originally posted</a> by DevilBoy
Todd it could be the brand of refractometer that is being used also....

That is true, it is the "blue" ATC one from Foster and Smith, I think I got it about 5 years ago. I am happy I got the solution to test it, but was pretty shocked that I was spot on.