Lesson learned about using R/O for refractometer calibration

[reeferfoxx]

Then I take a gallon to work and throw a YSI 6600 in there and get 35ppt like my refractometer says.

You are using the YSI6600 for salinity?

 

[reeferfoxx]

Nevermind I asked that. I would like to have one though lol

 

[Kaba]

A refractometer should be able to measure 0 and 35ppt accurately. But if you had to pick one, rodi would not be it. If you had a 35ppt standard you never have to calibrate your refractometer. If your 35ppt all of a sudden reads 40, and your tank reads 40...then your tank is really 35ppt.

 

[Paul B]

You guys like to spend money. I take my cheap swing arm hydrometer and throw it in my suitcase then drive to the airport. Get on a plane, preferably Jet Blue to a tropical destination where my fish comes from. Get out of the plane and rent a car, an American compact car. Drive to a marina and rent a boat. Sail out a few miles and find a shallow place where you can jump out of the boat, preferably near a mangrove Island. Bend down and put the thing in the water and hold it up. Take out a permanent marker and put a line on it where the arm is floating. (you may have to dry it off to do that) Get back in the boat and go back to the marina. Have a beer. Get in the car and take it to the airport. Get on the plane again and go home to test your water. You can save so much money by doing it this way.
Every time I buy a fish, I do this.

 

[BlackFish]

Must be nice to be filthy rich

 

[reeferfoxx]

You guys like to spend money. I take my cheap swing arm hydrometer and throw it in my suitcase then drive to the airport. Get on a plane, preferably Jet Blue to a tropical destination where my fish comes from. Get out of the plane and rent a car, an American compact car. Drive to a marina and rent a boat. Sail out a few miles and find a shallow place where you can jump out of the boat, preferably near a mangrove Island. Bend down and put the thing in the water and hold it up. Take out a permanent marker and put a line on it where the arm is floating. (you may have to dry it off to do that) Get back in the boat and go back to the marina. Have a beer. Get in the car and take it to the airport. Get on the plane again and go home to test your water. You can save so much money by doing it this way.
Every time I buy a fish, I do this.

Although it's funny and I get the humor, lets play with it and say someone actually did this with a hydrometer. Would altitude affect the SG between Point A(tropical island) and Point B(Home)?

 

[redfishbluefish]

You guys like to spend money. I take my cheap swing arm hydrometer and throw it in my suitcase then drive to the airport. Get on a plane, preferably Jet Blue to a tropical destination where my fish comes from. Get out of the plane and rent a car, an American compact car. Drive to a marina and rent a boat. Sail out a few miles and find a shallow place where you can jump out of the boat, preferably near a mangrove Island. Bend down and put the thing in the water and hold it up. Take out a permanent marker and put a line on it where the arm is floating. (you may have to dry it off to do that) Get back in the boat and go back to the marina. Have a beer. Get in the car and take it to the airport. Get on the plane again and go home to test your water. You can save so much money by doing it this way.
Every time I buy a fish, I do this.

You are totally wrong on your assessment.....you need to have two or three beers, if not more, to get accurate readings.


Actually a swing arm is accurately wrong, with consistency. If you "calibrate" your swing arm, and assure you have no bubbles in there, it will give you consistent results.

 

[Russ265]

False.

This device has a very large scale, and by calibrating with RO/DI you have assured the lowest reading will be accurate, but not mid-range (which we care about) or high range. As stated previously most hobby refractometers only have one calibration point rather than several. So we calibrate to the point closest to our use.

i never stated that setting your ro water to 0 gives correct results. the OP had to get negative refractive index just to make his salt right lol.

im stating that my calibrated ebay unit reads the same as my uncalibrated red sea unit that my marked hydrometer all agree with. (ro water is zero)

now if my calibrated refractometer read negative numbers with ro... its done. this isnt even a discussion. you have a shot piece of equipment.

by all means. bless your alibaba refractometers on a mountain high and as you point it to apollo for added hysteria pat yourselves on the back.

you made cheap junk work. when that cheap junk goes out of whack again is beyond me.


btw dont knock the hydrometer. by using broken refractometers you are essentially doing the same thing. you are not more accurate because you use a refractometer in this case.

 

[Kaba]

i never stated that setting your ro water to 0 gives correct results. the OP had to get negative refractive index just to make his salt right lol.

im stating that my calibrated ebay unit reads the same as my uncalibrated red sea unit that my marked hydrometer all agree with. (ro water is zero)

now if my calibrated refractometer read negative numbers with ro... its done. this isnt even a discussion. you have a shot piece of equipment.

by all means. bless your alibaba refractometers on a mountain high and as you point it to apollo for added hysteria pat yourselves on the back.

you made cheap junk work. when that cheap junk goes out of whack again is beyond me.


btw dont knock the hydrometer. by using broken refractometers you are essentially doing the same thing. you are not more accurate because you use a refractometer in this case.

RODI water at 25C has a specific gravity of 0.997g/cm3.

And a refractometer doesn't even need to have numbers honestly. If you measure the refraction of a 35ppt standard, and then have your tank water measure the same, then your tank water and the 35ppt standard have the same refractive index, and are thus in agreement.

And you saying "alibaba refractometer" and I have no idea what that means.

@reeferfoxx I have a 6600 in my lab at school that's used pretty sparingly. Unfortunately the probes are covered with copper anti-biofouling tape...so I can't exactly stick it in my sump.

 

[Russ265]

RODI water at 25C has a specific gravity of 0.997g/cm3.

And a refractometer doesn't even need to have numbers honestly. If you measure the refraction of a 35ppt standard, and then have your tank water measure the same, then your tank water and the 35ppt standard have the same refractive index, and are thus in agreement.

And you saying "alibaba refractometer" and I have no idea what that means.

@reeferfoxx I have a 6600 in my lab at school that's used pretty sparingly. Unfortunately the probes are covered with copper anti-biofouling tape...so I can't exactly stick it in my sump.

advocating the same terrible practice.

"just mark your bad measurement tool with the correct solution and you are covered....until a drop"

you are right. this method needs nothing other than a mark with nail polish on a lazy hydrometer.

but a hydrometer is mechanical, and id trust it's use over a refractometer any day of the week to justify this poor practice.

btw. your temperature of the sample will make a bigger difference than the .003 with a 0 rodi measurement. can you read within .003 in the first place? not the absolute static numbers... just the percent.

for reference.

 

[Kaba]

When did I advocate? I just you could. If your speedometer didn't work, you could just drive along side a friend on the highway and have them shout out every 5mph and you note the RPMs. Not the best solution, but a solution nonetheless.

But again, you don't need numbers on a refractometer or hydrometer. If you have 2 solutions are the same density, your hydrometer will read the same. Numbers on your measurement tool are irrelevant at this point. As long as one density is known, the other is equal.

 

[Russ265]

When did I advocate? I just you could. If your speedometer didn't work, you could just drive along side a friend on the highway and have them shout out every 5mph and you note the RPMs. Not the best solution, but a solution nonetheless.

But again, you don't need numbers on a refractometer or hydrometer. If you have 2 solutions are the same density, your hydrometer will read the same. Numbers on your measurement tool are irrelevant at this point. As long as one density is known, the other is equal.

quite right. i owe you an apology for assuming.

i DO think other variables should be stated before following this practice though.

 

[Paul B]

Although it's funny and I get the humor, lets play with it and say someone actually did this with a hydrometer. Would altitude affect the SG between Point A(tropical island) and Point B(Home)?

The altitude at sea level would be the same everywhere. If you live on top of Mount Everest, you will probably have other concerns other than salinity.
I also realize most, OK everyone will disagree with me, but salinity is not that important and doesn't have to be exactly anything as long as it is close to the environment your fish come from. So IMO which I discovered in 60+ years of doing this wrong. It isn't that important. But I know many people think perfection is the way to go so if you feel that way, buy a refractometer. Neither is temperature, "within reason" of course.

 

[Russ265]

The altitude at sea level would be the same everywhere. If you live on top of Mount Everest, you will probably have other concerns other than salinity.
I also realize most, OK everyone will disagree with me, but salinity is not that important and doesn't have to be exactly anything as long as it is close to the environment your fish come from. So IMO which I discovered in 60+ years of doing this wrong. It isn't that important. But I know many people think perfection is the way to go so if you feel that way, buy a refractometer. Neither is temperature, "within reason" of course.

my experience as well. i let my tank swing 1.023 to 1.028. no issues. no losses.

especially during water changes.

if salt reads 1.028 and the next morning it reads 1.030 i just bail a lil water.

i have bigger swings than a lot of you and my corals keep on ticking. check the acro grow off.

within 72 hours ill get 1.027-1.028 and call it a day though

 

[Kaba]

quite right. i owe you an apology for assuming.

i DO think other variables should be stated before following this practice though.

If you came home from a christmas eve party and your anemone was juiced by your powerhead, necessitating a big water change, ASAP, and you grabbed your refractometer and noticed (for some crazy reason) all the markings were gone, and you wouldn't be able to get a new one for a few days...then just comparing the refractive index of your new saltwater to the standard would work.
Other than a situation like that, I wouldn't recommend just comparing like that.

 

[Untamedrose]

You guys like to spend money. I take my cheap swing arm hydrometer and throw it in my suitcase then drive to the airport. Get on a plane, preferably Jet Blue to a tropical destination where my fish comes from. Get out of the plane and rent a car, an American compact car. Drive to a marina and rent a boat. Sail out a few miles and find a shallow place where you can jump out of the boat, preferably near a mangrove Island. Bend down and put the thing in the water and hold it up. Take out a permanent marker and put a line on it where the arm is floating. (you may have to dry it off to do that) Get back in the boat and go back to the marina. Have a beer. Get in the car and take it to the airport. Get on the plane again and go home to test your water. You can save so much money by doing it this way.
Every time I buy a fish, I do this.

Where is the RUM!

 

[dragonfish]

following

 

[Paul B]

Where is the RUM!

Back on the boat of course. I didn't want to spill it because those mangrove Islands don't need any Vodka (or rum) dosing. And the salinity there is perfect so they don't have to tweek it.

 

[revhtree Verified Admin]

Bump since this is a big topic today!