How to properly use milwaukee digital refractometer

[atticus]

All refractometers should be calibrated to zero? Hahahaha. Don’t know how he got that job.

Well BRS said I need to buy some calibration solution from them and calibrate both my digital and handheld refactor.

 

[Velcro]

Well BRS said I need to buy some calibration solution from them and calibrate both my digital and handheld refactor.

Most of the refractometers sold in the hobby aren't for seawater. They are on a brine (NaCl) scale. That means that calibrating it to zero with RODI or distilled water would NOT give you a correct reading for seawater readings. If the refractometer was on the seawater scale, like the redsea refractometer, then theoretically you could calibrate it to zero and it should read the correct ppt/SG with a seawater sample assuming that it is in perfect working condition.

For the BRS refractometer you absolutely want to calibrate it with one of the seawater refractometer solutions like the one in the white dropper bottle that they sell. I THINK the Milwaukee is also designed for seawater so it too can (and actually must) be calibrated with RODI or distilled water. The problem with the meter is that the accuracy is something like +/-0.002 SG which to me is not good enough for the price of the device.

 

[atticus]

The problem with the meter is that the accuracy is something like +/-0.002 SG which to me is not good enough for the price of the device.

Yup I think that’s what he said as far as the accuracy as well!

 

[Randy Holmes-Farley]

Well BRS said I need to buy some calibration solution from them and calibrate both my digital and handheld refactor.

I don’t think it is possible to calibrate the Milwaukee with anything but pure fresh water, but it can be checked after the fact with a 35 pot standard. [emoji3]

 

[Randy Holmes-Farley]

Don’t take this the wrong way because text has no emotion so not being an ***. I’m no scientist or chemist just stating what I was told from the head guy there. I’m still new to the hobby and had issues with mine reached out to BRS and they sent me to Milwaukee. Talk to the guy for about 30 min. and stated explaining stuff to me that was outta my league so took in as much as I could. He was stating that no matter what rodi unit I had that nothing is better than steamed distilled water. And went on to explain how both refactors work and as he stated that all refactors should always be calibrated to 0 and not to specific point.

I understand, and I understand why nonexperts would expect that a company rep would properly understand their product.

Unfortunately, many companies that sell chemical related products to the aquarium hobby don’t understand their own products. Sometimes it’s just a minor point, and sometimes it’s a massive inaccuracy (like the product is claimed to not alter alkalinity when it boosts it a lot, or that it really only adds half as much magnesium as claimed).

Inaccurate claims and explanations is a big part of why things like the Reef Chemistry forum are valuable. It’s not because we can regurgitate manufacturer recommendations, although that is often useful and all that is needed, but because, when needed, we can challenge them when they are wrong, confused, or just not clear enough to be useful.

 

[Randy Holmes-Farley]

do you recommend i use s.g, or ppt?

The units used make no difference. They are basically interchangeable, like measuring in feet or meters. Reefers online use both, but sg is more common.

 

[atticus]

I understand, and I understand why nonexperts would expect that a company rep would properly understand their product.

Unfortunately, many companies that sell chemical related products to the aquarium hobby don’t understand their own products. Sometimes it’s just a minor point, and sometimes it’s a massive inaccuracy (like the product is claimed to not alter alkalinity when it boosts it a lot, or that it really only adds half as much magnesium as claimed).

Inaccurate claims and explanations is a big part of why things like the Reef Chemistry forum are valuable. It’s not because we can regurgitate manufacturer recommendations, although that is often useful and all that is needed, but because, when needed, we can challenge them when they are wrong, confused, or just not clear enough to be useful.

What are your recommendations on reading salinity? I was possibly looking into getting a Apex system with salinity mod they offer.

 

[Randy Holmes-Farley]

What are your recommendations on reading salinity? I was possibly looking into getting a Apex system with salinity mod they offer.

If you have a quality device, all of floating glass hydrometers, conductivity meters, and refractometers can work very well. I personally prefer a digital conductivity meter that also reports temp at the same time. I use an old Orion model 128 (no longer sold new).

I'm not sure why, but some folks have issues with the Apex salinity measurement, maybe because of the user incorrectly setting up the temperature correction for the conductivity measurement (which is needed unless your tank is always at 25 deg C).

 

[XNavyDiver]

I was having some issues with mine and had a lengthy convo with man guy with tech support. To make sure that your unit is spot on accurate you need to be sure it is starting at true zero – ( zero is 1.000 SG )

First clean the base lens with Windex using a heavy Windex soaked Q-Tip or cotton ball – Then flush the Windex out of the pan by using the pipette we provide using “Steam Distilled Water” & do 2 or 3 loads of the pan and dump out or extract the distilled water using the pipette [ you MUST use “Steam Distilled Water” ] and then -- load the pan ½ way with “steam distilled water” ( you can’t use RO or DI water for this unit ) and press “zero” by doing this you are sure no residual salt or refraction material is on the lens– Another note: Your solution should always have a pan volume that is 1/3 to ½ full of distilled water for the zero and also that much of the tested sample. In addition, never double test the same sample – if you want to do a retest dump the first sample, flush the pan or blot out leftover first sample liquid and go back to the original source and get another sample. This is to prevent sedimentation of the sample that will give a distorted reading on the second reading.

To validate accuracy you should be using Seawater validation solution that is provided with your unit. @ ( 1.025 SG ) – Never use conductivity calibration solution. The reason is that Conductivity probes, like the Neptune and Pinpoint, are designed for NaCl testing and not Seawater. Most "validation" liquids for refractometers are made from Sodium Chloride [NaCl ] @ 99% - one of the providers of this on the internet is Sybon Scientific and there are others. The problem with their solution is that it is designed for Salinity validation not for Seawater. Their solution is Sodium Chloride [NaCl ] @ 99% and seawater is made up of Sodium Chloride [ NaCl ] @ 97% and Potassium Chloride [ KCl ] @ 2% and Other Trace Minerals Salts @ 1% and that 3% makes a huge difference.

Using this popular salinity liquid sellers, Sybon's, own chart http://www.premiumaquatics.com/prodimages/tropiceden/Sybon_refracto_cal_solution.jpg you will see that their solution is rated at 35ppt of Sodium Chloride and has a SG of 1.0264 SG and 53 mS/cm @ 77F which is their target for their salinity measurement units but that is for "Salinity Meters, Testers & Refractometers" not Seawater and their primary target is PPT/PSU or mS/cm. However, the optimum target for a seawater aquarium is 1.0250 sg @ between 68° F to 72° F (20/20). -- this brings up a point that all of this should be done at 70 F not 77 F.

The only way to validate your unit is with an independent actual seawater validation solution kit however if you are at +/- 0.001 SG you are within the units’ accuracy specification.

I bought mine used and it didn't come with a sea water validation solution. I'm not seeing anything called that on the Milwaukee website.

 

[XNavyDiver]

If you have a quality device, all of floating glass hydrometers, conductivity meters, and refractometers can work very well. I personally prefer a digital conductivity meter that also reports temp at the same time. I use an old Orion model 128 (no longer sold new).

I'm not sure why, but some folks have issues with the Apex salinity measurement, maybe because of the user incorrectly setting up the temperature correction for the conductivity measurement (which is needed unless your tank is always at 25 deg C).

Do have this correct Randy? 2.2 entered in the temp compensation?

 

[BigJohnny]

I have had mine for 3 years and love it. This is my procedure every time I test:

1. Fill half way with RODI, let sit for 3 mins, zero.
2. Dab/whipe clean and dry with toilet paper.
3. Fill half way with sample, let sit for 3 mins, test.
4. Hit test button a few more times to see if the reading is between two points or not.
5. Dab/whipe clean and dry with toilet paper.
6. Fill all the way with RODI
7. Dab/whipe clean and dry with toilet paper.

I think it's important to calibrate before each test because different lighting/temp can throw it off in my experience.

 

[Randy Holmes-Farley]

Do have this correct Randy? 2.2 entered in the temp compensation?

I don't know. I never used it. But assuming the temperature compensation entry is in units of % per deg C, I'd use 1.85, which is a pretty good fit for normal seawater.

 

[Reeflogic]

What I found is that bringing the temp up to the water to be tested is important, for me that is 79 degrees. I hold my palm over the metal cup thing until the temp is at 79, then test. I find I get accurate readings doing this. If I test with the unit at room temp, usually 70-73, I get lower readings than I should.

 

[Bruce Burnett]

Despite calibrating it with pure fresh water (in this case you must), it is still worth checking these with a standard 35 ppt solution to be confident in the answer.

Some folks have had issues with it, but I'm not sure why.

I don't know why people have problems. I can check mine with the solution they give and it is always correct. I think some maybe do not clean the lens on it well. I always shoot for 1.026 and then check it on ppt.

 

[Bruce Burnett]

They may have said that, but it simply isn't true. RO/DI with anything close to 0 ppm TDS is perfectly adequate. I can prove this mathematically, if you insist.



That too is simply incorrect.

The Pinpoint is a 35 seawater mimic and is suitable for refractometers. It is not just sodium chloride.

MY DIY for a refractometer is pure sodium chloride with refractive index of 35 ppt seawater. It is not 35 ppt sodium chloride, which would be inappropriate.

Both work perfectly for testing a seawater refractometer (when made correctly)

Ro/di works fine as I have zeroed mine with the distilled water that comes with it and ro/di got same readings. When I use mine and it read 35 ppt it will show 1.026 or 1.027 as expected and is close enough for any tank. I prefer it over the hand held refratometer as it is easy to read especiallywith bad eyes.

 

[cromag27]

I've had a few over the past many years and they have always been accurate enough to run healthy, full reefs as well as sps-only tanks. I always use their solutions.

You do need to be careful and make sure you don't drop it or jar it too hard, or else you'll mess up the mirror and your readings will be off.

 

[skiergd011013]

I've had a few over the past many years and they have always been accurate enough to run healthy, full reefs as well as sps-only tanks. I always use their solutions (it comes with 1.026 not 1.025, BTW).

You do need to be careful and make sure you don't drop it or jar it too hard, or else you'll mess up the mirror and your readings will be off.

the solution mine came with says 1.025 on the bottle. Yours is 1.026?

 

[cromag27]

No, I'm losing it. It's 1.025.

the solution mine came with says 1.025 on the bottle. Yours is 1.026?

 

[Pablo reefcabar]

Suppose that the specific gravity is 1.0255. You'd expect the reading to vary between 1.025 and 1.026.

True statement

 

[Pola0502ds]

This digital refractometer is by far one of the best purchases i have ever made. I really dont see how anyone can complain about it. Its off by 1 point? Come on man. Just test it once and move on.