Refractometers! How accurate are they?

MarkSativa · Sep 7, 2019

Refractometers! How accurate are they?

Does Calibration fluid go bad?

I recently bought a BRS Refractometer from my LFS. It came with some calibration fluid. My old refractometer seemed to work fine, but it was over 10 years old and had a little rust on the calibration screw, so I decided to get a new one.

I got the new meter home and checked the calibration with the new fluid.. Then checked it again with another fluid. I'm getting different readings from the 2 different fluids. I decided to go with the newer fluid and my new meter. I've made new saltwater cross checking with the new meter.

Now my green polyp toadstool has been closed all week The only thing I changed was the meter..

Has anyone else experienced this issue?

glb · Sep 7, 2019

Calibrated refractometers are pretty accurate IME. Did your adjustment make a big change to the salinity of the tank? That could irritate the corals.

flchamp89 · Sep 7, 2019

It has that waxy look like its in a shed.

Hersheyb · Sep 7, 2019

refractometers are ok if you keep them calibrated, as far as the calibration fluid I would replace them yearly just to be on the safe side. I eventually purchased the digital refractometer by Milwaukee and compared the results to my old refrac, it was off by .005.

romperstomper · Sep 7, 2019

I had one that was reading wrong (low) for sometime and my corals suffered ,then a red sea one that read different everytime ,D/D is the best so far with clear instructions on correct use .

bam123 · Sep 7, 2019

My brand new red sea refractometer had to be sent back for a new one as was very inconsistent. Customer care was good. I calibrate everytime before using. I also have the BRS with LED light. I like it better and it seems to be more consistent. I calibrate it with the solution as well. I also like to double check with RO water to make sure it's good.

MarkSativa · Sep 9, 2019

glb said:
Calibrated refractometers are pretty accurate IME. Did your adjustment make a big change to the salinity of the tank? That could irritate the corals.

Not that I noticed in the tank its self. I did adjust the up about .005. So when I bought the meter it was reading 1.021. So if the meter is wrong. I'm guessing my salinity could be a bit higher in my tank. Obviously I only did a 10 gallon water change because my system is roughly around 80 gallons with the sump. So the swing in salinity should not be that bad.

MarkSativa · Sep 9, 2019

flchamp89 said:
It has that waxy look like its in a shed.

I hope that is what it is. I had a toadstools in my old system. It would close up for a day or two, but this toadstools has been closed for over a week now.

MarkSativa · Sep 9, 2019

Hersheyb said:
refractometers are ok if you keep them calibrated, as far as the calibration fluid I would replace them yearly just to be on the safe side. I eventually purchased the digital refractometer by Milwaukee and compared the results to my old refrac, it was off by .005.

As I mentioned on another comment.. mine seems to be off by .005

MarkSativa · Sep 9, 2019

romperstomper said:
I had one that was reading wrong (low) for sometime and my corals suffered ,then a red sea one that read different everytime ,D/D is the best so far with clear instructions on correct use .

Thank you for your input..

MarkSativa · Sep 9, 2019

bam123 said:
My brand new red sea refractometer had to be sent back for a new one as was very inconsistent. Customer care was good. I calibrate everytime before using. I also have the BRS with LED light. I like it better and it seems to be more consistent. I calibrate it with the solution as well. I also like to double check with RO water to make sure it's good.

That is something I have not looked at yet. Why I haven't checked my RO is beyond me. Brain fart we will say. Thanks for the advice..