Different Salinity Readings

[Mogwai]

Ok so... I've had my tank going for 1 week now and so far so good until I used 2 Hydrometers +/-0.003 (Instant Ocean) and a refractometer +/-0.006 (Calibrated with RODI water) and all 3 are giving me a different Specific Gravity readings. I am nervous that I either have too much or too little salinity. Any suggestions and help would be great as far as what to do and which piece of equipment i should use? Thx in advanced

 

[Garf]

Ok so... I've had my tank going for 1 week now and so far so good until I used 2 Hydrometers +/-0.003 (Instant Ocean) and a refractometer +/-0.006 (Calibrated with RODI water) and all 3 are giving me a different Specific Gravity readings. I am nervous that I either have too much or too little salinity. Any suggestions and help would be great as far as what to do and which piece of equipment i should use? Thx in advanced

Its probably an error to calibrate a refractometer with RODI, even if the manufacturer said to do so. You can make a DIY solution for pennies or buy proper 35ppt refractometer calibration solution.

 

[Gtinnel]

The easiest way to test the accuracy of a refractometer is to buy or make a calibration solution of a known salinity. Use it to verify that your refractometer reads it at the correct level. If you have some basic kitchen scales it's easy to make the solution with water and regular table salt.
I assume it would probably work with hydrometers, but I haven't used one in about 15 years. So I'm not confident saying that it absolutely would.

 

[N.Sreefer]

First thing I would do is check the tds on the rodi water to make sure the refractometer is on. Make sure the water you used to calibrate with is close to tank temp. Refractometer is def the more accurate option those swing arm hydrometers suck. Could try calibration solution if you cant get the calibration down with the rodi.

 

[KStatefan]

Calibrate with 35 ppt solution

http://reefkeeping.com/issues/2006-12/rhf/index.php

http://www.reefkeeping.com/issues/2004-06/rhf/index.php

 

[Mogwai]

First thing I would do is check the tds on the rodi water to make sure the refractometer is on. Make sure the water you used to calibrate with is close to tank temp. Refractometer is def the more accurate option those swing arm hydrometers suck. Could try calibration solution if you cant get the calibration down with the rodi.

I'm using a 6 stage RODI unit bought from Bulk Reef Supply. There should be no TDS in that water. Before each use I back flush then flip the switch as per their recommendations.

 

[KStatefan]

I'm using a 6 stage RODI unit bought from Bulk Reef Supply. There should be no TDS in that water. Before each use I back flush then flip the switch as per their recommendations.

do not make assumptions measure and verify

 

[Shirak]

I'm using a 6 stage RODI unit bought from Bulk Reef Supply. There should be no TDS in that water. Before each use I back flush then flip the switch as per their recommendations.

Your refractometer will not read saltwater correctly if calibrated with rodi

 

[Ramdude4G]

I know this in gonna sound mean or rude but I promise I’m not trying to be. For what you spent on both those cheaper salinity checkers you could have bought the Hana digital one. I think it was like $65. I know it’s a bit more expensive but well worth it. Especially for a checker that you will be using over and over again. It also comes with 5 or 10 calibration samples. Spend the money where its needed most and will benefit you the most. it also shows the temp of the water you are checking. I use mine daily and well worth the money spent. I didn’t want to spend the money at first either but I’m glad that that was the only one my FLS had at that moment. Eventually majority of my tests will be Hana. With the exception of a few. Just remember. You are testing the life support for your pets. You should want the best equipment you can afford for that. To get the most accurate results.

 

[Mogwai]

I know this in gonna sound mean or rude but I promise I’m not trying to be. For what you spent on both those cheaper salinity checkers you could have bought the Hana digital one. I think it was like $65. I know it’s a bit more expensive but well worth it. Especially for a checker that you will be using over and over again. It also comes with 5 or 10 calibration samples. Spend the money where its needed most and will benefit you the most. it also shows the temp of the water you are checking. I use mine daily and well worth the money spent. I didn’t want to spend the money at first either but I’m glad that that was the only one my FLS had at that moment. Eventually majority of my tests will be Hana. With the exception of a few. Just remember. You are testing the life support for your pets. You should want the best equipment you can afford for that. To get the most accurate results.

I honestly was looking into the Hanna Salinity Tester before I posted the thread. Im a review kind of individual and I've read so many bad and good reviews with that product. I may buy it and try it for myself and no... not rude nor do you sound rude. Lol.

 

[Ramdude4G]

Hom

I honestly was looking into the Hanna Salinity Tester before I posted the thread. Im a review kind of individual and I've read so many bad and good reviews with that product. I may buy it and try it for myself and no... not rude nor do you sound rude. Lol.

Honestly I don’t have one bad complaint about it. I’m like you. I’m a review junkie. But I guess every product has a bad apple every now and then. Doesn’t mean the product is bad just a particular component used in the product. Also means some people just can’t be pleased no matter what. And some people just have it out for a particular brand and will post negative reviews regardless. So when reading the bad reviews you kinda have to take them with a grain of salt so to speak. Now there are some Hana tests that are not the optimal choice. But then that merely falls on your matter of choice.

 

[Shirak]

I honestly was looking into the Hanna Salinity Tester before I posted the thread. Im a review kind of individual and I've read so many bad and good reviews with that product. I may buy it and try it for myself and no... not rude nor do you sound rude. Lol.

I have the Hanna salinity tester. I use it more now vs the refractometer since I made some DYI calibration solution and I can verify it is reading accurately. Mine seems to work great and then for some reason it will go off by a few points usually to the low side. I got tired of dealing with the calibration packets so I made a jar of reference solution so I can do a quick check and if needed hit the calibration button.