I don’t know which Salinity tester to trust

[RWReefer]

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

Just coming back to say this was genius. Thanks for the input. Don’t even have to turn off the ATO because the volume doesn’t register enough to trigger.

 

[JulesH]

The key with the hanna checker (any instrument in fact) is to keep it calibrated, mine drifts over a quite short period of time. Now I use the Tropic Marin high precision hydrometer, not as convenient as a Hanna checker but as long as you can read off the scale correctly it's easy.

 

[Christine Rawlings]

as others stated always have a refractometer as backup. also, which of the two matched the calibration liquid? if one matched, then thats the correct one.

The Hannah matched and I am going to take this advice and have back up. Thank you!

 

[BeanAnimal]

Ive used Hannah and haven't had issues, but a hydrometer will be the most accurate.

A precision floating, not a swing arm.

 

[BeanAnimal]

The Hannah matched and I am going to take this advice and have back up. Thank you!

Highly recommend then TM precision floating hydrometer and a 500ml graduated cylinder.

 

[allieW]

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.

You can get the britewell calibration liquid. It will help you know 4 sure what is accurate.

 

[allieW]

You can get the britewell calibration liquid. It will help you know 4 sure what is accurate.

Amazon.com

 

[NTLA]

A precision floating, not a swing arm.

Yeah, sorry I should have been more specific

 

[Sdoutreefer]

Highly recommend then TM precision floating hydrometer and a 500ml graduated cylinder.

This.

I've had very accurate readings with the TM hydrometer.

 

[Key Largo]

Lots of differing opinions here. I’ll just add a few of mine:

1. Exact salinity is not critical for reef aquarium use.

2. Nearly any device we use can and should be checked for accuracy. Some can be calibrated and some you can just determine an offset to use manually.

3. High quality conductivity meters are expensive, are very accurate if properly calibrated (when possible) and have uses that are not readily performed with other devices (kalkwasser potency, acclimation salinity in real time, etc).

Have to agree with Randy here. On his advice/recommendation, originally having to do with Kalk saturation, I purchased a conductivity meter and never looked back. The easiest thing to use and calibrate, and has multiple uses (salinity/kalk). Pinpoint makes a reasonably priced one.

 

[KStatefan]

Have to agree with Randy here. On his advice/recommendation, originally having to do with Kalk saturation, I purchased a conductivity meter and never looked back. The easiest thing to use and calibrate, and has multiple uses (salinity/kalk). Pinpoint makes a reasonably priced one.

Which one did you purchase?

 

[djkms]

Hanna Salinity tester for me

it is the only tester on the market that measures a tenth of a point in PPT that I am aware of. Since I have a large system this is critical for me. A couple gallon difference in my system is only .1ppt which most testers can't test for. going from 1.027 to 1.026 is probably 20+ gallons and that's a really big correction.

I will say though, it drifts and needs to be recalibrated often. I recalibrate every month and may switch to every 2 weeks. I will also say to use Randy's DIY calibration solution, its basically free. It is the only solution that matched perfectly to ICP. The Hanna solution was 1ppt lower:

Salinity - 34.5 Hanna | 35.6 DIY | 1.026.5 Refract | 35.6 Oceamo ICP-MS

One thing to keep in mind in my opinion. We are not measuring the salt content of the water (sodium chloride). We are measuring the total amount of ions in the water. Your calcium content is different at 34ppt then it is at 35ppt. So is your magnesium, potassium, strontium, etc, etc. This is why its important to keep this consistent as it plays an important role in all your elements.

 

[robottaway]

Using a $17 refractometer with two calibration fluids to dial it in. Have tested many times and it has held settings without fail. Reef is happy so not gonna sweat perfect. Hydrometer is the way to go IMO if you want that, I just don’t use one right now only have a low volume tank.

 

[areefer01]

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.

It is a fragile device. I wouldn't float it in the display. Purchase a 500 ml glass cylinder like the image below of your choice and use that. Easy enough to fill up with tank water or freshly made, test, and what not.

 

[Christine Rawlings]

It is a fragile device. I wouldn't float it in the display. Purchase a 500 ml glass cylinder like the image below of your choice and use that. Easy enough to fill up with tank water or freshly made, test, and what not.

I just purchased 2 of these! One for each tank

 

[Christine Rawlings]

Hanna Salinity tester for me

it is the only tester on the market that measures a tenth of a point in PPT that I am aware of. Since I have a large system this is critical for me. A couple gallon difference in my system is only .1ppt which most testers can't test for. going from 1.027 to 1.026 is probably 20+ gallons and that's a really big correction.

I will say though, it drifts and needs to be recalibrated often. I recalibrate every month and may switch to every 2 weeks. I will also say to use Randy's DIY calibration solution, its basically free. It is the only solution that matched perfectly to ICP. The Hanna solution was 1ppt lower:

Salinity - 34.5 Hanna | 35.6 DIY | 1.026.5 Refract | 35.6 Oceamo ICP-MS

One thing to keep in mind in my opinion. We are not measuring the salt content of the water (sodium chloride). We are measuring the total amount of ions in the water. Your calcium content is different at 34ppt then it is at 35ppt. So is your magnesium, potassium, strontium, etc, etc. This is why its important to keep this consistent as it plays an important role in all your elements.

I ended up buying the high precision hydrometer so now I can compare it to my Hannah checker and know when it needs to be calibrated. I feel more confident with having both of them now.

 

[Christine Rawlings]

Which one did you purchase?

I ended up buying the high precision hydrometer from Tropic Marin.

 

[RWReefer]

It is a fragile device. I wouldn't float it in the display. Purchase a 500 ml glass cylinder like the image below of your choice and use that. Easy enough to fill up with tank water or freshly made, test, and what not.

This was mentioned earlier and one has been purchased and received. Definitely makes things much easier. Appreciate the heads up!

 

[areefer01]

This was mentioned earlier and one has been purchased and received. Definitely makes things much easier. Appreciate the heads up!

I may have missed it - apologies.

 

[RWReefer]

I may have missed it - apologies.

It’s important enough to highlight twice. Great recommendation.