Tires of salinity problems

[Rscott]

I can not get my salinity stable to save my life
It’s clear the apex probe is complete garbage. I have recalibrated it 3 times and it’s only 3 months old

I have 4 different refractometers and 4 different bottles of calibration fluid, they all read different

Spend the money on the Hannah checker last night and. Guess what, it reads different also

I have no clue which one to believe all I know is my SPS is ticked off because the salt is bouncing all Over

I can never get in the 34 range it’s either in 32 or 37

The apex probe seems to continuously read low
This is a big problem because I have an auto water change system and need to check my main 100 gallon salt tank for it

I don’t know what the solution is but an ideas would be helpful! Thanks everyone

 

[Crossfire]

I've noticed that my refractometers read a bit different too but only from 1.024-1.027. The trick is to choose one refractometer or the Hannah checker and stick with that one exclusively. Remember the rule of keeping your parameters stable over chasing numbers. You stick with one salinity checker for all your water changes and you'll be stable.

From what I noticed, corals and fish don't mind anything from 1.023-1.028 as long as they stay steady at whatever number you're at. Obviously the goal is 1.026 but if your tank is plus or minus .001 it really doesn't matter too much. If the apex probe is giving you trouble, just turn it off.

I only check my salinity of my new water and again after my water change. Once it's done, it will stay stable as long as it is topped off with Ro/di so the water level remains the same.

I think you have too much of a good thing with all these different refractometers. None of them are perfect. Again, stick with one and only use that. Calibrate it every month or so and don't over think it.

 

[Flippers4pups]

I've noticed that my refractometers read a bit different too but only from 1.024-1.027. The trick is to choose one refractometer or the Hannah checker and stick with that one exclusively. Remember the rule of keeping your parameters stable over chasing numbers. You stick with one salinity checker for all your water changes and you'll be stable.

From what I noticed, corals and fish don't mind anything from 1.023-1.028 as long as they stay steady at whatever number you're at. Obviously the goal is 1.026 but if your tank is plus or minus .001 it really doesn't matter too much. If the apex probe is giving you trouble, just turn it off.

I only check my salinity of my new water and again after my water change. Once it's done, it will stay stable as long as it is topped off with Ro/di so the water level remains the same.

I think you have too much of a good thing with all these different refractometers. None of them are perfect. Again, stick with one and only use that. Calibrate it every month or so and don't over think it.

Well said!

 

[Taxus812]

I use a Hanna. First tip is heat the calibration fluid to tank temp. the second is calibrate using the 7ph and the 10ph calibration fluids (calibrate between the typical range you use). As for the refractometers, f they are intended to calibrate to 0TDS RODI you typically cant use calibration fluids to calibrate. the calibration will be off.

If I use for example: If I try my 7.0- ph calibration fluid for my HANNA on my refractometer it is way off. However if I use RODI on my refractometer the Hanna and Refractometer are the same.

I also agree with above pick one and stick with it. I like my Hanna for ease of use. I calibrate once a month.

 

[Crossfire]

I use a Hanna. First tip is heat the calibration fluid to tank temp. the second is calibrate using the 7ph and the 10ph calibration fluids (calibrate between the typical range you use). As for the refractometers, f they are intended to calibrate to 0TDS RODI you typically cant use calibration fluids to calibrate. the calibration will be off.

If I use for example: If I try my 7.0- ph calibration fluid for my HANNA on my refractometer it is way off. However if I use RODI on my refractometer the Hanna and Refractometer are the same.

I also agree with above pick one and stick with it. I like my Hanna for ease of use. I calibrate once a month.

Good point. I use 0 TDS RO/DI to calibrate my refractometers too. Works fine for me.

 

[FugeTown]

I use RODI water and then I calibrate it to zero then I put my tank water on my refractometer same amount of drops that I put when I calibrated and seems to always be on point. I have two of the cheap hydrometers that both match up to my refractometer. I tried the 35 ppt solution but had big problems with it so since calibrating with RODI I haven’t had a problem. They are very sensitive so you gotta also make sure the glass is clean when calibrating with the rodi water.

 

[Jay Z]

I had the same issues also. Nothing would read the same. Went to a apera digital salinity checker. Only thing that seems to hold true.

 

[Rscott]

I use RODI water and then I calibrate it to zero then I put my tank water on my refractometer same amount of drops that I put when I calibrated and seems to always be on point. I have two of the cheap hydrometers that both match up to my refractometer. I tried the 35 ppt solution but had big problems with it so since calibrating with RODI I haven’t had a problem. They are very sensitive so you gotta also make sure the glass is clean when calibrating with the rodi water.

Glass is clean???
I am utterly confused with some of the suggestions

There is no glass with this device

 

[W1ngz]

Like above, just pick one and stick with it. A few notes:

There is glass on a refractometer. For my refractometer I flush it and my dropper with RODI, then flush it again with tank water, then add a test sample.

RODI isn't the best choice for calibrating refractometers. Scientific equipment should be calibrated at or within the range of expected results.

Refractometer calibration fluid works only on refractometers. You can't use it for digital stuff, as they work on conductivity of seawater. The calibration fluid has a specific refractive index, it doesn't have the same conductivity of seawater.

 

[Randy Holmes-Farley Verified Community Expert]

I can not get my salinity stable to save my life
It’s clear the apex probe is complete garbage. I have recalibrated it 3 times and it’s only 3 months old

I have 4 different refractometers and 4 different bottles of calibration fluid, they all read different

Spend the money on the Hannah checker last night and. Guess what, it reads different also

I have no clue which one to believe all I know is my SPS is ****** off because the salt is bouncing all Over

I can never get in the 34 range it’s either in 32 or 37

The apex probe seems to continuously read low
This is a big problem because I have an auto water change system and need to check my main 100 gallon salt tank for it

I don’t know what the solution is but an ideas would be helpful! Thanks everyone

Salinity is always adequately stable if the tank is filled to the same level (assuming you are not leaking salt water). The testing results may be unstable.

 

[Randy Holmes-Farley Verified Community Expert]

Good point. I use 0 TDS RO/DI to calibrate my refractometers too. Works fine for me.

How do you know it works fine?

 

[Randy Holmes-Farley Verified Community Expert]

I use a Hanna. First tip is heat the calibration fluid to tank temp. the second is calibrate using the 7ph and the 10ph calibration fluids (calibrate between the typical range you use). As for the refractometers, f they are intended to calibrate to 0TDS RODI you typically cant use calibration fluids to calibrate. the calibration will be off.

If I use for example: If I try my 7.0- ph calibration fluid for my HANNA on my refractometer it is way off. However if I use RODI on my refractometer the Hanna and Refractometer are the same.

I also agree with above pick one and stick with it. I like my Hanna for ease of use. I calibrate once a month.

That is untrue. If you calibrate a refractometer using an actual 35 ppt fluid intended for refractometers, IT CANNOT be off for measuring 35 ppt (a few electronic refractometers cannot be calibrated this way due to the software, but still must read it correctly)

if you use RO/DI, it could be off and you would never know it.

 

[FugeTown]

That is untrue. If you calibrate a refractometer using an actual 35 ppt fluid intended for refractometers, IT CANNOT be off for measuring 35 ppt (a few electronic refractometers cannot be calibrated this way due to the software, but still must read it correctly)

if you use RO/DI, it could be off and you would never know it.

My refractometer specifically says in the instructions to calibrate to 0 with rodi , I can trust that because I know it’s 0. When I buy a bottle of 35 ppt I have no idea who made it even if it’s actually 35 ppt. Like I said before I have 2 hydrometers that work great especially the glass bobber one I used for my brewing ki. They both agree with my refractometer after calibrating it to zero with rodi. I’m no scientist and I’m sure there’s some scientific reason you guys know that’s over my head but I like simple methods that work and must of gotten lucky because it’s been working great for me. Another confirmation is when I mix my saltwater with the same salt to rodi ratio the refractometer still always reads the same after calibrating to 0 with rodi. I think it’s cause I’m very particular on how many water drops I put on it and that I clean the glass very well. Randy buddy your giving me an idea for another YouTube video experiment this topic gets my juices flowing.

 

[Sisterlimonpot]

Outside of digital units that can't be calibrated to 35ppt, it is never a good idea to calibrate with 0 tds water at 0ppt when you're measuring salinity at or around 35ppt.

None of the refractometer that are sold to hobbyist are considered lab grade. A $30 refractometer needs to be calibrated to the range in which you intend to use it.

If you want to test water to ensure it's at 0ppt then calibrate it to 0.

If you want to test water to ensure it's at 35ppt then calibrate it to 35.

 

[FugeTown]

Outside of digital units that can't be calibrated to 35ppt, it is never a good idea to calibrate with 0 tds water at 0ppt when you're measuring salinity at or around 35ppt.

None of the refractometer that are sold to hobbyist are considered lab grade. A $30 refractometer needs to be calibrated to the range in which you intend to use it.

If you want to test water to ensure it's at 0ppt then calibrate it to 0.

If you want to test water to ensure it's at 35ppt then calibrate it to 35.

How do you know for sure your getting 35ppt fluid in a little $5 bottle? Just because you trust the label? My refractometer isn’t digital and was more than 30 bucks. Plus like I said I have two different types of hydrometers to double check if the refractometer seems off. The manufacturer instructions tell you to calibrate to 0ppm and it works believe it or not. Maybe it’s a newer model IDK but works for me and better than trusting that snake oil.

 

[Sisterlimonpot]

How do you know for sure your getting 35ppt fluid in a little $5 bottle? Just because you trust the label? My refractometer isn’t digital and was more than 30 bucks. Plus like I said I have two different types of hydrometers to double check if the refractometer seems off. The manufacturer instructions tell you to calibrate to 0ppm and it works believe it or not. Maybe it’s a newer model IDK but works for me and better than trusting that snake oil.

The only thing I can say to that is, you have to trust it's 35ppt. Have you heard reports that these bottles of 35ppt samples aren't within specifications?

As long as the bottle was sealed properly at the factory, and during shipment it didn't get damaged, I would trust it over calibrating to zero.

The calibration adjustment on a refractometer is mechanical, and we rely heavily on setting the angle of the view finder to refract precisely at the range we want to test. If you adjust the angle by using 35ppt then when measuring 35ppt it will be spot on... anything above and below that 35ppt starts to become skewed due to the mechanical limitations of the refractometer. The further away from 35ppt the less accurate your reading.

If you're calibrating a mechanical refractometer to 0 then your reading at/or around 35ppt will be skewed.

If you feel that the snake oil is a flawed mixture and cant trust it, then calibrating to 0 might be what makes you sleep at night.

Although if you don't trust the snake oil, you can easily make your own 35ppt calibration fluid. Randy has a recipe for that... it's not hard to do. once you see how easy it is to make your own, you'll realize that it's hard for a manufacturer to screw it up. which is why I would trust the bottle of snake oil over calibrating to 0.

 

[Taxus812]

That is untrue. If you calibrate a refractometer using an actual 35 ppt fluid intended for refractometers, IT CANNOT be off for measuring 35 ppt (a few electronic refractometers cannot be calibrated this way due to the software, but still must read it correctly)

if you use RO/DI, it could be off and you would never know it.

Thanks for the correction. My Intent was to say you can’t use the same calibration fluid for one type of tester for another (electronic testers calibration fluid for a refractometer) it will not calibrate properly.

The OP mentioned he had a probe tester that was way off and I wanted to make sure her was not using the same calibration fluid.

 

[Randy Holmes-Farley Verified Community Expert]

My refractometer specifically says in the instructions to calibrate to 0 with rodi , I can trust that because I know it’s 0. When I buy a bottle of 35 ppt I have no idea who made it even if it’s actually 35 ppt. Like I said before I have 2 hydrometers that work great especially the glass bobber one I used for my brewing ki. They both agree with my refractometer after calibrating it to zero with rodi. I’m no scientist and I’m sure there’s some scientific reason you guys know that’s over my head but I like simple methods that work and must of gotten lucky because it’s been working great for me. Another confirmation is when I mix my saltwater with the same salt to rodi ratio the refractometer still always reads the same after calibrating to 0 with rodi. I think it’s cause I’m very particular on how many water drops I put on it and that I clean the glass very well. Randy buddy your giving me an idea for another YouTube video experiment this topic gets my juices flowing.

All claim to use ro/di. Don’t believe it without further understanding. Manufacturers are often not your best source of reef chemistry information.

Some refractometers are true seawater refractometers. Almost always they say so. If they are, and if they are made and functioning and used perfectly, they can be calibrated with ro/di. They can also be calibrated with a 35 ppt standard, and that will give a correct calibration for 35 ppt seawater even if they are not made or used perfectly. It is never, ever wrong to use a properly made standard.

Many (most) refractometers used by hobbyists are brine (NaCl) refractometers repurposed by enterprising resellers to be used in seawater. While they are intended to be calibrated in ro/di, doing so will give slightly inaccurate values in seawater, even if made and used perfectly. If imperfect, the answers may be even further off. In this case, it is much better to use a standard.

In short, it is never wrong to use a 35 ppt standard, and often will give better values.

 

[Randy Holmes-Farley Verified Community Expert]

How do you know for sure your getting 35ppt fluid in a little $5 bottle? Just because you trust the label? My refractometer isn’t digital and was more than 30 bucks. Plus like I said I have two different types of hydrometers to double check if the refractometer seems off. The manufacturer instructions tell you to calibrate to 0ppm and it works believe it or not. Maybe it’s a newer model IDK but works for me and better than trusting that snake oil.

Snake oil implies a misleading product. If you educate yourself, you may laugh at your own writing.

 

[Crossfire]

How do you know it works fine?

Simple- everything in my tank is doing well.

Could it be off, yeah maybe but not by much. My other refractometer are all close. If I started changing things, I'll end up like the guy who started this thread about chasing a perfect number. That's where the trouble begins.

I agree it's best to calibrate it will calibration fluid and won't argue using RO/DI. It's just what I do, and my corals are growing beautifully. I'm no expert/professional in the field like you are, but I try my best. If it's working for me, I'm not changing a thing.