Keeping Salinity Stable. ATO?

[Bryan47]

If 35 ppt and sg = 1.0264 do not line up, it is a brine refractometer and not a true seawater refractometer.

If you calibrate it with a 35 ppt standard, you can set it for 35 ppt or sg = 1.0264, then stick with reading whichever unit of measure you set correctly.

Randy I have a question for you. Another customer at a pet store told me using RODI for saltwater tanks wasn't good and it was too filtered. I disagreed with him but I said I would ask the genius that is Randy Holmes-Farley. So is RODI worse than just plain filtered water? I assume he meant like using a Brita type filter.

 

[that Reef Guy]

If 35 ppt and sg = 1.0264 do not line up, it is a brine refractometer and not a true seawater refractometer.

If you calibrate it with a 35 ppt standard, you can set it for 35 ppt or sg = 1.0264, then stick with reading whichever unit of measure you set correctly.

I have heard about this.

Does it say on the packaging when you buy one if it is seawater or brine?

Or do you have to test it to know?

 

[Bryan47]

It's the brs one

 

[Randy Holmes-Farley Verified Community Expert]

Randy I have a question for you. Another customer at a pet store told me using RODI for saltwater tanks wasn't good and it was too filtered. I disagreed with him but I said I would ask the genius that is Randy Holmes-Farley. So is RODI worse than just plain filtered water? I assume he meant like using a Brita type filter.

RO/DI is perfect for a marine system. There's nothing in tap water that you want that isn't already in a salt mix.

RO/DI is too clean for a fresh water tank (except it is fine for top off or small water changes). Most creatures cannot live in pure deionized water. Folks generally add some salts if they are going to use it for a fresh water setup.

 

[Randy Holmes-Farley Verified Community Expert]

I have heard about this.

Does it say on the packaging when you buy one if it is seawater or brine?

Or do you have to test it to know?

Almost never will it say brine. I think true seawater refractometers are typically going to make that claim on the package, however.