Salinity Now (part 2)

[Wavemode]

I just received my Milwaukee refractometer yesterday and it's telling me my salinity is 1.027 in my 50 gallon cube, 29 gallon nano cube, and my brute garbage can full of cooking pukani. I calibrated it with RODI. My ATC refractometer says 1.025 which I calibrated with 35 ppm calibration solution. My coral life hydrometer reads 1.024 which I don't trust but wanted a third reference. Can someone tell me if the Milwaukee is the most accurate? I'm a little freaked out about salinity after recently finding out mine has been wrong for months because of bad information I got off YouTube.

 

[Reeferdood]

What kind of bad info did you get off you tube?
Did all of the refractomers read the same off the calibration fluid?
I'd use what ever one is closest to your calibration solution. Also, that has been known to go bad as well.
Stability is key, try for 1.025-6 and you should be fine.

 

[reeferfoxx]

I had the same concern with my milwuakee meter. Turns out the calibration fluid and 35ppt fluid were both off. I would try a different 35ppt solution to make sure you get the correct reading. That said, I think the milwuakee is more accurate than the hydrometer and spy glass refractometer.

 

[Wavemode]

When I got my ATC refractometer I saw a video on YouTube that said to calibrate it with RODI water. I found out 3 months later when watching a BRS video and Ryan said to never use RODI. Only use calibration fluid because it's closer SG to the water you want to check. When I got the fluid I found out my reef had been at 1.022 for months. So now I'm extra cautious asking lots of questions. Especially after watching my critters suffer and not know what I was doing wrong.

 

[Reeferdood]

Questions are always good, never a dumb question here.. That is why it is a forum, everyone is trying to help out.
So, with that being said, I would stick with the Milwaukee and get two different solutions to calibrate it, perhaps you will get a warm fuzzy that way. Randy has Recipes if you want to try that as well..

 

[reeferfoxx]

When I got my ATC refractometer I saw a video on YouTube that said to calibrate it with RODI water. I found out 3 months later when watching a BRS video and Ryan said to never use RODI. Only use calibration fluid because it's closer SG to the water you want to check. When I got the fluid I found out my reef had been at 1.022 for months. So now I'm extra cautious asking lots of questions. Especially after watching my critters suffer and not know what I was doing wrong.

When I first started reefing I filled the tank and measured with hydrometer. Two weeks later my ATC came in the mail. According to that my salinity was off by 0.004sg. Not a big deal but a year later I bought the milwuakee and noticed again my salinity were off by at least 0.002. I do like the milwuakee and sometimes it's better to keep consistency with one meter.

 

[Wavemode]

Questions are always good, never a dumb question here.. That is why it is a forum, everyone is trying to help out.
So, with that being said, I would stick with the Milwaukee and get two different solutions to calibrate it, perhaps you will get a warm fuzzy that way. Randy has Recipes if you want to try that as well..

I appreciate the input. The Milwaukee came with two fluids I've been trying to learn how to use and you had a great idea to use the ATC fluid as a third and RODI as a fourth.

 

[Wavemode]

When I first started reefing I filled the tank and measured with hydrometer. Two weeks later my ATC came in the mail. According to that my salinity was off by 0.004sg. Not a big deal but a year later I bought the milwuakee and noticed again my salinity were off by at least 0.002. I do like the milwuakee and sometimes it's better to keep consistency with one meter.

Was your Milwaukee reading higher? Everything I try this thing says is 0.002 higher than any other source. Sounds like I should stabilize my tanks to the Milwaukee and just stay there. Thanks for your help!

 

[reeferfoxx]

Was your Milwaukee reading higher? Everything I try this thing says is 0.002 higher than any other source. Sounds like I should stabilize my tanks to the Milwaukee and just stay there. Thanks for your help!

Yes. My milwuakee was reading 0.001 higher than calibration fluid. You can talk to customer service and see if they cant send you new fluids to cal and test with?

 

[jason2459]

Keep in mind the digital will round up.

And this thread may be relevant
http://reef2reef.com/threads/does-your-calibration-solution-need-calibrated.250133/

 

[XyPP]

Milwaukee specifies +/- 0.002.

So your results are not abnormal.

 

[Randy Holmes-Farley Verified Community Expert]

Fortunately, all of the readings, from 1.024 to 1.027 are fine.

 

[Wavemode]

Hi Randy, Thanks for the response. I tried 4 different calibration fluids in the Milwaukee and every one reads 0.002 higher than what it states on the bottles. The instructions for the refractometer have no mention on how to adjust that error out. Are we just supposed to adjust it out theoretically in our heads or am I missing something?

 

[jason2459]

Hi Randy, Thanks for the response. I tried 4 different calibration fluids in the Milwaukee and every one reads 0.002 higher than what it states on the bottles. The instructions for the refractometer have no mention on how to adjust that error out. Are we just supposed to adjust it out theoretically in our heads or am I missing something?

Mental. There's no adjustment and it's only means of calibration is with distilled or RODI water. I wish it had higher resolution and two point calibration.

 

[Wavemode]

Mental. There's no adjustment and it's only means of calibration is with distilled or RODI water. I wish it had higher resolution and two point calibration.

I can live with that. If it's always off the exact same amount every time then it will be fairly easy to get my salinity precisely where I want it and keep it there. Thanks for helping me with this issue.

 

[BigHildy53]

The Milwaukee MA887 Seawater Digital Refractometer I purchased from BRS said to only use steam distilled water for the zero out calibration. The manual said to use distilled or deionized; however a "manual update page" (lack of a better term) with the packaging said to only use steam distilled. I take a sample to a LFS every now and then to compare. Too much light can effect it also, I always cup my hand over the refactor.

 

[jason2459]

.... Too much light can effect it also, I always cup my hand over the refactor.

I do that as well during calibration and readings. Seems to help.

 

[Wavemode]

The Milwaukee MA887 Seawater Digital Refractometer I purchased from BRS said to only use steam distilled water for the zero out calibration. The manual said to use distilled or deionized; however a "manual update page" (lack of a better term) with the packaging said to only use steam distilled. I take a sample to a LFS every now and then to compare. Too much light can effect it also, I always cup my hand over the refactor.

I appreciate your advice. I've tried the steam distilled and the 1.025 samples that came with the refractometer both with my hand cupped over the prism and without. I also tried the same tests with RODI and the calibration fluid made for the monocular type refractometers. This Milwaukee unit is consistently 0.002 higher when reading anything that has a salt content. I guess going into this I thought this tool would be more capable of telling me exactly what my salinity is which it does. I just have to remember subtract 0.002 every time.

 

[roberthu526]

I trust the Milwaukee more than any refractometer. I calibrate with distilled water though as suggested in the manual.

 

[Wavemode]

Yes I agree. This one is a definite winner. I remember being skeptical when I got my first Hanna checker. Now I have every one they make for saltwater and I trust their results.