Test your refractometer

[thepipbull]

While visiting Lazy's today another member came in and had his refractometer tested with the calibration fluid and the results were way off.
Calibration fluid calibrates to sg 1.026 or 35ppt. His refractometer was 1.031 which would cause his tank water to be 1.021. Kinda low...
He told me he used the distilled water to calibrate it to zero like the instructions from the refractometer tell you do do.
I also have only calibrated with distilled water and was curious so I brought so fluid home and tested my 2 refractometers and was surprised to see both of them at 1.031. Cleaned them and tested again and same results. So I dug thru all my old equipment and found a hydrometer and tested my tanks and all were 1.020.
So glad i used the Calibration fluid instead of the distilled water.
The lower salinity could be attributing to some issues I've experienced lately. going to do some water changes and raise it to 1.025 of the next few weeks.
We will also start including the Calibration fluid in the club test kit for all premium member wishing to use!!

[CoralBeauties]

One more thing to add is to warm your calibration fluid to the temp of your tank water that you are usually testing.  The temp difference can also change the readings.  when I calibrate I drop my calibration fluid bottle into my sump before I calibrate.
jeff

[Wall_Tank]

my $0.02

I use the Milwaukee Digital Seawater Refractometer, it calibrates using distilled water.  From what I've seen, devices calibrated against a zero reference when checked with calibration fluid will read about 0.002 high.  I personally don't think the offset is a huge problem.

1) Definitely pick a calibration method and do it.  Don't use distilled water one time, and then calibration fluid the next time.
2) Whatever you use for calibration fluid, make sure you are careful to not contaminate it.

[Grymtooth]

Tested mine this morning with fluid from Lazy, read 1.028, so not too shabby there, tank still at 1.026 after calibration

Sent from my SM-N910V using Tapatalk