Help with salinity problem please?

[Cobrasvt1999]

Heya guys,

I was about to run a water change in my system when I decided to try my good ol' Hanna salinity tester as opposed to my refractometer, and now I dont know who to believe. Hope you guys can shed some light on this.

with the refractometer calibrated with RODI water at 0ppt, my tank was readying 35ppt
However, the Hanna was reading 31ppt. I tried calibrating it with the 35ppt calibration solution, and its still reading 31ppt, it reads the calibration fluid at 35ppt after calibration

I tried calibrating the refractometer with the 35ppt Hanna solution and it now reads the tank at 41ppt and RODI at 10ppt, so thats not too believable....

My thought is that the Hanna is the accurate one and somehow my refractometer is all over the place? hard to imagine how a prism breaks, but there you go.... All tests are repeatable just in case I was somehow screwing them up...

I have to travel tomorrow for work, but will be doing a tiebreaker by taking a sample to a LFS when I get back, but in the meantime, what are your guy's thoughts? which one do I trust?

P.S. my fish and corals are all happy.... so theres that, just dont actually feel confident in my salinity anymore.

 

[jonelder68]

I’d throw the Hanna in the trash. It swings so much and never holds a calibration. Be done and buy a TM hydrometer and never have to question again.

 

[Cobrasvt1999]

I’d throw the Hanna in the trash. It swings so much and never holds a calibration. Be done and buy a TM hydrometer and never have to question again.

Soo, trust the good ol refractometer calibrated off RODI? Haven't used a Hydrometer since I worked at a fuel station... Gotta imagine the process is the same

 

[jonelder68]

I would over the hanna. I literally threw mine in the trash.

 

[mpatterson42]

My Hanna salinity tester always read 2ppt lower than multiple other instruments so I stopped using it.

 

[AgentKooper]

I’d throw the Hanna in the trash. It swings so much and never holds a calibration.

That has not been my experience at all. My Hanna tester also read considerably lower than my refractometer (to the extent I could ever get a consistent result from the refractometer). I threw my refractometer in the trash and have been happily reefing with the Hanna for a couple years now.

 

[jonelder68]

This and a 500ml cylinder is all you’ll ever need. So cheap buy two incase you break one.

 

[bridge2smooth]

Right now, I’d trust the Hanna (after calibration) because you cannot ensure the calibration of your refractometer. What I see is the Hanna solution cannot be reliable for refractometer because the solution is based for electric conductivity at 35ppt and not truly 35ppt for calibrating refractometer.

Also, I learned this the hard way as well, but even though a lot of the refractometers say to calibrate with RODI, it’s unreliable. That’s because if you notice when you are turning the calibration screw at 0, you can still turn it and it will stay at 0. So you can’t really trust a calibration at 0.

So it’s way more accurate to calibrate the refractometer with a dedicated calibration solution for refractometers. I wouldn’t trust it until you do this!

 

[jonelder68]

That has not been my experience at all. My Hanna tester also read considerably lower than my refractometer (to the extent I could ever get a consistent result from the refractometer). I threw my refractometer in the trash and have been happily reefing with the Hanna for a couple years now.

My Hanna would swing .005 ppm per use. Can even calibrate. Check salinity. 5 minutes later recheck and will be different reading. That’s no good in my book. The thermometer on it is consistently inaccurate also. So explains the bad salinity readings. TM hydrometer is error proof as long as waters 77 degrees it has slim to no errors possible.

 

[jonelder68]

For refractometer do a DIY calibration solution for accurate results. Here’s a link to Randy’s recipe…

DIY Salinity calibration solutions

Randy, In light of another post on calibrating a conductivity meter, I decided to give it all a shot on my own system. I read through your article on DIY salinity calibration (http://www.reefkeeping.com/issues/2004-06/rhf/) and have a few questions for my simple brain. 1. Is the Brand MORTON...

www.reef2reef.com

 

[Randy Holmes-Farley]

One cannot assume that calibration solutions designed for different types of devices are interchangeable. They often are not.

I’d make your own calibration fluids for the different devices you have, and calibrate using those.

 

[Cobrasvt1999]

One cannot assume that calibration solutions designed for different types of devices are interchangeable. They often are not.

I’d make your own calibration fluids for the different devices you have, and calibrate using those.

Just did this following your fantastic article and now both the hanna and the refractomiter are measuring the same salinity in the tank. That article is a god send and explains things so well, thank you so much for taking the time to write it out!

 

[Sawacoral]

Mine has always functioned out of the box this way and after calibrating. It’s unusable.

 

[jonelder68]

Just did this following your fantastic article and now both the hanna and the refractomiter are measuring the same salinity in the tank. That article is a god send and explains things so well, thank you so much for taking the time to write it out!

Now try the Hanna tomorrow and compare to the test solution and see how far it’s off. Recalibrate then try again. It will give different readings every time! Throw it out!

Refractometer calibrated on Randy’s recipe people have good results.

Or just buy a TM hydrometer and no worries ever!

 

[exnisstech]

I've had two of the Hanna checkers (I'm a slow learner) and I trashed them both for the reasons listed above. I'm now using a TM hydrometer to confirm new saltwater is 1.025 salinty at 77 degree's. I then use that fresh batch to calibrate my refractometers. I do this every 7 days which is how often I mix a new batch of water. I only use the refractometers for spot checks of the tanks between changes which I don't do very often because my tank salinty doesn't change enough to need adjusted..

 

[Cobrasvt1999]

Now try the Hanna tomorrow and compare to the test solution and see how far it’s off. Recalibrate then try again. It will give different readings every time! Throw it out!

Refractometer calibrated on Randy’s recipe people have good results.

Or just buy a TM hydrometer and no worries ever!

Will try this. Always annoying when a company sells a product as ready that probably needs another few years in R&D....

 

[KStatefan]

Just for a different experience made a batch of new saltwater this morning Tropic Marin Hydrometer 1.0261 after temp correction. Hanna which I have not calibrated in a long time 1.026. The Hanna normally reads 0.001 lower than the tropic marin hydrometer.

 

[reef2021]

This and a 500ml cylinder is all you’ll ever need. So cheap buy two incase you break one.

My hanna is great and holds a calibration but I have a hard time trusting the reading after I calibrate it which makes this hydrometer incredibly useful. I use it to verify my hanna’s calibration in freshly made salt water before a water changes periodically. If my hanna is off I just record how off it is and go from there.

Every so often though I put it my reef because of it’s accuracy just for fun!

 

[Mr. Mojo Rising]

Personally I love my hanna tester and use it exclusively for the past 5 years. I have 3 tanks at different salinity for exactly this reason (1.024, 1.025, 1.026) and the hanna tests them perfectly each week for me.