Lesson learned on Salinity

[jwshiver]

Careful with the RedSea, you have to calibrate it every time you use it with 35ppt calibration solution.

I've noticed the same problem with mine. Need to find another brand. Does anyone have any suggestions? I looked at the Milwaukee Digital but apparently it has a +/- .002 accuracy. If shooting for 1.025 that's a range of 1.023 to 1.027. No thanks.

 

[d2mini]

Careful with the RedSea, you have to calibrate it every time you use it with 35ppt calibration solution.

Read the Red Sea manual!
You calibrate it with RO water, not calibration fluid.
Not that it probably makes that much of a difference, but if you want to be as accurate as possible...

And yes, you do need to calibrate pretty much every time. I still don't understand how it goes widely out of calibration so quickly.
But it is supposed to be VERY accurate when calibrated.

OP, sorry for your troubles! That sucks.

Lesson here for everyone is to calibrate your refractometers often, and if you see a big change in your salinity readings, calibration should be your first step before taking any other action.

 

[Randy Holmes-Farley]

If you do get a controller, do not rely on the conductivity probe to be an accurate and reliable indicator of salinity. It's more there for you to recognize consistency and trends. Invest in a Milwaukee digital refractometer, one my most valued reefing tools by far. Plus I'm blind as a bat and have a hard time reading a regular refractometer!

Nonsense. Conductivity probes are easily calibrated and checked, and generally are the method used by scientists. Only hobbyists use refractometers.

 

[Randy Holmes-Farley]

Read the Red Sea manual!
You calibrate it with RO water, not calibration fluid.
Not that it probably makes that much of a difference, but if you want to be as accurate as possible...
.

It can NEVER be inaccurate to use a proper 35 ppt salinity standard. In some cases it can be technically impossible but anytime you can, it is perfectly accurate.

 

[d2mini]

It can NEVER be inaccurate to use a proper 35 ppt salinity standard. In some cases it can be technically impossible but anytime you can, it is perfectly accurate.

I didn't say it was INaccurate.
I'm saying you don't need to use calibration solution. No reason to go out and buy it when the instructions clearly state to use RO water.
If Red Sea felt that it was better to use calibration fluid, they would have said so. So like I said, it may not make a noticeable difference, but I'd just go with what they recommend. And it's easier/cheaper!

 

[Water Dog]

The big problem I had with the Red Sea refractometer was I would calibrate it, take my reading, then immediately recalibrate it again just to make sure... sure enough, it would be off again. It literally drifted in the span of 3 minutes! :mad:

 

[Randy Holmes-Farley]

I didn't say it was INaccurate.
I'm saying you don't need to use calibration solution. No reason to go out and buy it when the instructions clearly state to use RO water.
If Red Sea felt that it was better to use calibration fluid, they would have said so. So like I said, it may not make a noticeable difference, but I'd just go with what they recommend. And it's easier/cheaper!

No matter what manufacturers claim, there are reasons to use a standard other than RO/DI.

A perfectly designed and perfectly manufactured true seawater refractometer can be correctly calibrated with Ro/DI. If you totally trust them, go for it.

Even an imperfectly designed (e.g., brine refractometers, which make up the bulk of those sold to hobbyists) or imperfectly manufactured refractometer can be correctly calibrated to read 35 ppt seawater using a 35 ppt seawater standard. If you have any question about its accuracy, a good standard will eliminate the concern.

So it all boils down to who you trust.

 

[roger saltwaters]

No matter what manufacturers claim, there are reasons to use a standard other than RO/DI.

A perfectly designed and perfectly manufactured true seawater refractometer can be correctly calibrated with Ro/DI. If you totally trust them, go for it.

Even an imperfectly designed (e.g., brine refractometers, which make up the bulk of those sold to hobbyists) or imperfectly manufactured refractometer can be correctly calibrated to read 35 ppt seawater using a 35 ppt seawater standard. If you have any question about its accuracy, a good standard will eliminate the concern.

So it all boils down to who you trust.

Good to know. I might get some and try that. I've always wondered why Red Sea wandered around so much. This should eliminate that problem.

 

[d2mini]

In this case, I trust Red Sea.
I use calibration fluid on my ebay refractometer, and RO on Red Sea as they instruct.
And no, using calibration fluid won't magically keep the Red Sea calibration constant.

 

[jason2459]

IME, the RedSea refractometer was the absolute worse at maintaining calibration of all the refractometers I've ever used. Which includes a handful of cheap ebay/amazon/store labeled "saltwater" refractometers, D2Ocean seawater, Veegee/Vitalsine, and a Milwakee digital. Not to meantion other methods such as a floating hydrometer, pinpoint conductivity probe, and two Apex conductivity probes.

I would also highly suggest at least using a standard solution near the point you want to measure like a 35ppt reference standard even if you calibrate at 0. Like the Milwaukee seawater digital refractometer there is no other choice but I will still use a 35ppt solution to validate accuracy which I really wish it allowed you to select which reference you want to calibrate to or even better a 2 point calibration.

FWIW, I've found over time inaccuracy of store bought calibration solutions and use Randy's recipe to make my own now.
https://www.reef2reef.com/threads/does-your-calibration-solution-need-calibrated.250133/

 

[hart24601]

I trust Randy!

 

[RamsReef]

As mentioned calibration doesn't really matter with proper practice.
My procedure is as follows.
Check tank, wipe, check tank, wipe, check new water, wipe, check new water, wipe, check new water.
Do the check new water once as you are adjusting new water to make new water.

Once in a while I will check my RO/DI water to 0 right now it's around 1.01 but I don't care as I'm just matching new water to old.

I'm not dismissing having the proper calibration though, don't get me wrong.

 

[FindNem0]

Wow I didn't expect this much feed back. You know what talks? Post your aquariums. Let's see the reefs!!! Like I said earlier, you can't find the wealth of knowledge that's wrapped up in this post in a book, experience!!!!!! You can't teach experience. I thought I was experienced, but obviously I Nuged this one up. (Nug = New Usless guy)

Thanks for all the insight. I always said the controller took the fun out of the hobby, but it's worth spending the money if you're going to have a couple grand in corals. I just found a vertex controller for $400. Can the probes be recalibrate? Or do they have to be replaced once wet

 

[Maacc]

Wow I didn't expect this much feed back. You know what talks? Post your aquariums. Let's see the reefs!!! Like I said earlier, you can't find the wealth of knowledge that's wrapped up in this post in a book, experience!!!!!! You can't teach experience. I thought I was experienced, but obviously I Nuged this one up. (Nug = New Usless guy)

Thanks for all the insight. I always said the controller took the fun out of the hobby, but it's worth spending the money if you're going to have a couple grand in corals. I just found a vertex controller for $400. Can the probes be recalibrate? Or do they have to be replaced once wet

Be careful, the vertex, being brand new is having a number of issues. You can go for it, just be careful.

 

[FishLover01]

Just a thought for you. I use a refractometer as well and have calibration fluid for it as well. I think most of the calibration fluids for the majority of refractometers is set at 1.026SG or 35ppt. I use this fluid about every time before I read salinity. As a cross check, I have one of the hydrometers with a suction cup that stays in the tank attached to the front glass. Yes, this hydrometer is not totally accurate but I can tell good enough when it's getting a little high. I'd recommend you get one of these types along with a good refractometer. Sorry for the financial loss you incurred. Painful, but you learned a great lesson the hard way which in time will make you a way better reefer. Good Luck Man!!!

 

[jwshiver]

The big problem I had with the Red Sea refractometer was I would calibrate it, take my reading, then immediately recalibrate it again just to make sure... sure enough, it would be off again. It literally drifted in the span of 3 minutes! :mad:

Same

 

[jwshiver]

I use http://www.bulkreefsupply.com/aqua-craft-refractometer-calibration-fluid.html and float it in my sump for 15 minutes to get it up to temperature. If I'm reading the label correctly the solution is calibrated for 77 degrees. Warmer than my room temp here in Florida.

 

[ciscomania]

Don't waste your money on refractometer and just get yourself the milwaukee digital refractometer and you will feel confident about your salinity level. Probably the best purchase I made for this hobby next to ATO.

 

[salty150]

I've noticed the same problem with mine. Need to find another brand. Does anyone have any suggestions? I looked at the Milwaukee Digital but apparently it has a +/- .002 accuracy. If shooting for 1.025 that's a range of 1.023 to 1.027. No thanks.

Have you found anything more accurate than +/- .002?

 

[jason2459]

Have you found anything more accurate than +/- .002?

That's actually not very good there are many with higher. One of my complaints about the Milwaukee digital besides how it's calibrated would be I wish it had higher resolution. I'd like to read out to at least the tenths place in PSU mode.