Red Sea Hydrometers

[1329eheim]

They stink. I find it has to be re calibrated (with 35 ppt calibration fluid) before each use (or may read as much as 5 ppt lower than it should) and that the scale (ppt vs SG) is off. E.G., 35 ppt = incorrect 1.025 SG, instead of correct 1.026(4). Am I crazy or has anyone else noticed these flaws?

 

[Kworker]

Do you mean Refractometer?

 

[HefeWeizen]

Get a refractometer. They are more accurate and can be easily calibrated.

 

[1329eheim]

Do you mean Refractometer?

Yes. Thanks!

 

[Kworker]

I have the same issue with the red sea refractometer. I can't adjust it however since I accidentally let the calibrating screw rust... its designated as my QT refractometer, it serves the purpose as long as I keep in mind the variation.

 

[HefeWeizen]

If it's a refractometer, why don't you calibrate with RO/DI water to 0.0?

 

[Aquadicted]

hm..... i havent had to calibrate my refractometer for a long time...My screws are also pretty rusted :/

Honestly at this point, I can guess pretty accurately how much salt to use and I just check that way if my refractometer is CLOSE to where it should be. Complete accuracy in salinity is not important for me unless I'm hypoing.

 

[skunkcleaner]

Didn't do mine for couple moths and finally decided to pick up some calibration fluid .. Turns out was 1.023 when reading 1.026 .. If your looking at getting a new one check out the Milwaukee digital refractometer

 

[Brando457]

I have the Milkwaukee digital, it is good for the most part. Sometimes it can be finicky and I have to recalibrate it a few times, but overall I like it.

 

[skunkcleaner]

I have the Milkwaukee digital, it is good for the most part. Sometimes it can be finicky and I have to recalibrate it a few times, but overall I like it.

Do u happen to have the Milwaukee ulr phosphate checker ? Thinking about buying it and curious of your thoughts if u have it

 

[1329eheim]

If it's a refractometer, why don't you calibrate with RO/DI water to 0.0?

Assuming you're not busting my chops, refractometers are calibrated at 35 ppm, not 0.

Mike

 

[skunkcleaner]

When u calibrate with ro/di water u calibrate it to 0

35 when using a solution

 

[1329eheim]

When u calibrate with ro/di water u calibrate it to 0

35 when using a solution

Hmmm. But why would you want to test ro/di water with refractometer, rather than TDS meter?

Mike

 

[Chefjpaul]

Hmmm. But why would you want to test ro/di water with refractometer, rather than TDS meter?

Mike

Your not testing the water, you are calibrating the refractometer. It's same results as recalibration fluid only it reads 0.0 instead of 35

 

[1329eheim]

Oh, ok. But, according to BRS, Randy Holmes Farley, Boomer, and other chemists, you will not get an accurate reading if you calibrate using RO/DI water. That's why the calibration fluid for refractometers is set at 35 ppt, the salinity of NSW.

http://www.bulkreefsupply.com/aqua-craft-refractometer-calibration-fluid.html

http://www.drsfostersmith.com/product/prod_display.cfm?pcatid=18717

It makes sense to me because the goal of using a refractometer is to make sure that the salinity of replacement water or DT water I'm testing is as close to 35 ppt as possible. But if RO/DI water works as calibration fluid for you, that's fine by me.

Good luck,

Mike

 

[HefeWeizen]

If your TDS is zero then it will be pretty damn close to a zero. I'm not willing to pay $9 for a vial of seawater.

Funny thing is I also have an old school hydrometer and it consistently reads the same as my refractometer.

 

[skunkcleaner]

I was actually going to post that I tried with mine and it was still off from the calibration fluid

 

[Chefjpaul]

I was actually going to post that I tried with mine and it was still off from the calibration fluid

Me too, I just did as I was curious.

Funny because as I transitioned into using the fluid vs. the rodi a couple years ago, I never compared the two, I never thought of it. Good topic to bring up as I know a few LFS only using water to calibrate.

I guess it's more about stability anyway, unless it's way...way off, which mine was not enough to be an issue.

But- If you calibrate it with rodi to read zero, it will be accurate to test your salt water as it had an accurate base line to begin with.