Unexpected problem with refractometers... lol

Randy Holmes-Farley · Mar 14, 2017

https://www.reef2reef.com/threads/how-to-do-saltwater-change.294826/#post-3607308

"I personally lost an entire reef 8 months ago because my two little boys took my refractometer apart and my wife put it back together without telling me. "

slipknotgrrl83 · Mar 14, 2017

I always calibrate mine before using. I actually splurged last week though and bought a digital from Milwaukee. I hope that never happens to me !

drawman · Mar 14, 2017

I currently have two calibration fluids that are both relatively new from the same company that are off by several points. I guess for me precision is better than accuracy.

slipknotgrrl83 · Mar 14, 2017

I try to keep at 1.025 so that way if it's off a point either way I'm still in the "safe " zone

drawman · Mar 14, 2017

slipknotgrrl83 said:
I try to keep at 1.025 so that way if it's off a point either way I'm still in the "safe " zone

+1. Corals have looked good so I know I'm not off too far I just wish there was a little more quality control with standards.

Randy Holmes-Farley · Mar 14, 2017

drawman said:
I currently have two calibration fluids that are both relatively new from the same company that are off by several points. I guess for me precision is better than accuracy.

Hard to know without further testing if it is the fluids or the refractometer giving variable results.

Lionfish Lair · Mar 14, 2017

Mine always makes me nervous because I've never had to adjust it during calibration. It's about 10 years old.

slipknotgrrl83 · Mar 14, 2017

drawman said:
+1. Corals have looked good so I know I'm not off too far I just wish there was a little more quality control with standards.

Same!

jason2459 · Mar 14, 2017

drawman said:
I currently have two calibration fluids that are both relatively new from the same company that are off by several points. I guess for me precision is better than accuracy.

Make your own.

GoFish · Mar 14, 2017

+1 to making your own. Moral of that story is keep them away from your kids! And wife sheesh...

I was using Pinpoint calibration fluid thinking it was better than following the directions (calibrate with distilled water) on a Marine Depot Refractometer. My buddy was having wonky results using his new bottle of Sybon calibration Fluid. Long story short is my Pinpoint was out by 0.001 (1.025 reading was actually 1.026) and his Sybon fluid was 0.0025 (1.0285 was actually 1.026). He had his refractometers double checked with 2 new bottles of fluid at the store and cross checked with another refractometer.

Randy, what's the deal with a seawater refractormeters being more reliable or appropriate to use with our tanks VS salinity refractometers? Have the stores been selling us the incorrect tool?

p7willm · Mar 14, 2017

A refractometer is measuring the difference in the speed of light in the air and in the liquid. They do not directly measure the specific gravity of the liquid or the number of particles in the liquid. They take that speed difference and tell you how dense or how much of a specific item dissolved in another item would cause the difference. If you dissolve an equal amount of salt, sodium chloride, and the stuff in sea water, sodium chloride and a lot of other stuff, in water the speed of light will change differently. The difference between a salinity and a salt water refractometer is how they interpret the change in speed.

They also make refractometers that are designed to tell how much sugar is dissolved in water that are used to test grapes.

Randy Holmes-Farley · Mar 15, 2017

GoFish said:
+1 to making your own. Moral of that story is keep them away from your kids! And wife sheesh...

I was using Pinpoint calibration fluid thinking it was better than following the directions (calibrate with distilled water) on a Marine Depot Refractometer. My buddy was having wonky results using his new bottle of Sybon calibration Fluid. Long story short is my Pinpoint was out by 0.001 (1.025 reading was actually 1.026) and his Sybon fluid was 0.0025 (1.0285 was actually 1.026). He had his refractometers double checked with 2 new bottles of fluid at the store and cross checked with another refractometer.

Randy, what's the deal with a seawater refractormeters being more reliable or appropriate to use with our tanks VS salinity refractometers? Have the stores been selling us the incorrect tool?

Yes, folks who sell brine refractometers (and for a long time, those were mostly what was available), and recommend RO/DI for calibration when used for seawater are selling a bill of goods.

I expect most were simply unaware of the issue. But that's no excuse.

fetta · Mar 15, 2017

Ok maybe a newbie question, but how do you make your own fluid

AllSignsPointToFish · Mar 15, 2017

fetta said:
Ok maybe a newbie question, but how do you make your own fluid

Here is one of Randy's articles on the subject:
http://www.reefkeeping.com/issues/2004-06/rhf/

Paul B · Mar 15, 2017

Randy, sometimes those precise scientific instruments can be a problem. That's why I take my seven dollar, 15 year old swing arm hydrometer to a coral reef and jump in the water with it. Then I mark a line on it where the thing is floating and use that forever. No testing, no calibration, no nothing but seven bucks and $5,000.00 to get to a coral reef. Simple.

GoVols · Mar 15, 2017

Randy Holmes-Farley said:
https://www.reef2reef.com/threads/how-to-do-saltwater-change.294826/#post-3607308

"I personally lost an entire reef 8 months ago because my two little boys took my refractometer apart and my wife put it back together without telling me. "

lol,
Randy we just had a thread on the below not long ago.

Another one of his lines:
Be sure you use calibration solution or fresh RO water before using your refractometer to make sure you refractometer is calibrated.

Anybody Following...
Trust me... Don't zero out your meter to RO water. Use 35 solution, it does makes a different.

Maacc · Mar 15, 2017

Paul B said:
Randy, sometimes those precise scientific instruments can be a problem. That's why I take my seven dollar, 15 year old swing arm hydrometer to a coral reef and jump in the water with it. Then I mark a line on it where the thing is floating and use that forever. No testing, no calibration, no nothing but seven bucks and $5,000.00 to get to a coral reef. Simple.

Keys or Caribbean?

GoVols · Mar 15, 2017

Maacc said:
Keys or Caribbean?

Lol

GoVols · Mar 15, 2017

Paul B said:
Randy, sometimes those precise scientific instruments can be a problem. That's why I take my seven dollar, 15 year old swing arm hydrometer to a coral reef and jump in the water with it. Then I mark a line on it where the thing is floating and use that forever. No testing, no calibration, no nothing but seven bucks and $5,000.00 to get to a coral reef. Simple.

Lol,

"Post of the Year", Contender??????????