I don’t know which Salinity tester to trust

[Christine Rawlings]

Had been using an Ice Cap tester for the longest and then went out and bought a Hannah tester to compare. These were my results and any ideas on which one to trust or what to compare it to? I attempted to calibrate both of them to 35ppm using solution provided by Hannah. Attached picture.

 

[AetherealKnight]

If possible I would ask for a second opinion from your local reef store. Personally I would side with the Hannah as I don’t have any experience with ice cap..

 

[Christine Rawlings]

If possible I would ask for a second opinion from your local reef store. Personally I would side with the Hannah as I don’t have any experience with ice cap..

Thank you, I did take some water to a LFS today and no one was there not the best city for LFS reliability but I might still do that another day. Appreciate it!

 

[AetherealKnight]

Thank you, I did take some water to a LFS today and no one was there not the best city for LFS reliability but I might still do that another day. Appreciate it!

Maybe you can do a home experiment to find out. Just get a 2 gallon bucket fill it up to exactly 2 gallons and then pour exactly 1 cup of salt. In theory we know that the mixture creates a salinity of 1.026. And use that as a baseline to test the ice cap and Hannah to see which is more accurate.

 

[Christine Rawlings]

Maybe you can do a home experiment to find out. Just get a 2 gallon bucket fill it up to exactly 2 gallons and then pour exactly 1 cup of salt. In theory we know that the mixture creates a salinity of 1.026. And use that as a baseline to test the ice cap and Hannah to see which is more accurate.

Perfect, thank you. I will let you know what I find.

 

[KStatefan]

Perfect, thank you. I will let you know what I find.

Randy has a good article on DIY calibration standards

https://reefkeeping.com/issues/2004-06/rhf/index.htm

 

[WalkerLovesTheOcean]

Refractometers are easily the most accurate and reliable salinity tester to use. So if you get no luck with trying to figure out which one is accurate, I suggest buying a refractometer.

 

[RWReefer]

Tropic Marin high precision hydrometer will be right each time without the need to recalibrate.

 

[BriDroid]

I bought a used Ice Cap pen this week. It’s the “newer” style with the off and cal buttons.

I mixed up some of Randy’s DIY calibration solution and calibrated it. It seems to be dead on since then. I honestly really like it.

 

[Christine Rawlings]

Tropic Marin high precision hydrometer will be right each time without the need to recalibrate.

You had me at no need to recalibrate. Looking into that now.

 

[RWReefer]

You had me at no need to recalibrate. Looking into that now.

I will note that it most likely will require you to shut off your powerheads in order to work correctly (calm water). That’s the only “complaint” I’ve got. The only equipment I have that I have 100% confidence in every time.

 

[Mr. Mojo Rising]

You can get a packet of Hanna calibrater and test it, they are set at 1.026. I have a bunch at home, they cost a buck each.

Ask a buddy for a baggie of water and ask his salinity and test it yourself.

When I buy corals I always ask the salinity and check myself when I get home. Same with fish.

I have 3 tanks at home 2 are at 1.025 and one is at 1.024.

These are the ways I know my Hanna tester is 1000% right on.

 

[Formulator]

Refractometers are easily the most accurate and reliable salinity tester to use. So if you get no luck with trying to figure out which one is accurate, I suggest buying a refractometer.

This is the answer ^^^

Unless you are tying into a continuous monitor, there is no need for fancy electronic testers. A refractometer is based on elementary physics and as suggested is easily the most accurate and least error prone method. Almost like a sun dial, there is almost nothing that can go wrong.

More power to you if you prefer the digital readout, but at the very least you could use a refractometer to tell you which meter is most accurate and even calibrate with it. They are like $15 on amazon.

 

[Mechano]

Tropic Marin high precision hydrometer will be right each time without the need to recalibrate.

This is the best method that’s fool proof.
I’ve used refractometers, and salinity pens in the past, and different hydrometers (like IO) but I just never trusted them.

The TM high precision is a perfect and accurate tool for the job. As long as the temp is around 77 degrees, it’s accurate as you can get with hobby grade testers

 

[RWReefer]

This is the best method that’s fool proof.
I’ve used refractometers, and salinity pens in the past, and different hydrometers (like IO) but I just never trusted them.

The TM high precision is a perfect and accurate tool for the job. As long as the temp is around 77 degrees, it’s accurate as you can get with hobby grade testers

Good point. The temperature is the one variable that needs to be dialed in.

 

[EricR]

I will note that it most likely will require you to shut off your powerheads in order to work correctly (calm water). That’s the only “complaint” I’ve got. The only equipment I have that I have 100% confidence in every time.

500mL cylinder... shut off ATO,,, scoop,,, measure,,, done.

 

[RWReefer]

500mL cylinder... shut off ATO,,, scoop,,, measure,,, done.

Can’t turn off the Tunze without dumping in about 25 seconds of RO/DI as it primes the line on restart (unless there is a setting I’m missing). But I am going to try and utilize this strategy somehow.

 

[EricR]

Can’t turn off the Tunze without dumping in about 25 seconds of RO/DI as it primes the line on restart (unless there is a setting I’m missing). But I am going to try and utilize this strategy somehow.

Interesting -- I run Tunze Nano Osmolator -- and force it to restart every time by purposely bouncing water level down briefly -- minimum runs seem to be about 10 seconds but sometimes I'll hear up to about 30 seconds.

*that was long babble but even 30 seconds run means very little to me in my tiny 40G tank

 

[Christine Rawlings]

I will note that it most likely will require you to shut off your powerheads in order to work correctly (calm water). That’s the only “complaint” I’ve got. The only equipment I have that I have 100% confidence in every time.

Thank you, and I want 100% confidence.

 

[RWReefer]

Interesting -- I run Tunze Nano Osmolator -- and force it to restart every time by purposely bouncing water level down briefly -- minimum runs seem to be about 10 seconds but sometimes I'll hear up to about 30 seconds.

*that was long babble but even 30 seconds run means very little to me in my tiny 40G tank

Just ran the numbers and 500mL would be about 0.15% of my system volume. Doubt the ATO would even register it so I’m gonna give it a shot. Thanks for sharing that strategy!

OP, sorry for hijacking. I still think the TM hydrometer is the bees knees.