Instant ocean salt

[BubblesandSqueak]

First I would like to thank everyone for there replies.
With all the replies stating that the 1/2 cup per gallon should be right, I decided it must be some kind of measurement error/testing error.
This is my conclusion. My rodi water has a tds of 5. I'm not concerned about that, it has always tested at 5ppm. The tds of the calibration solution should be 3500ppm. My tester does not read that high. I am only getting a tds off 250ppm on the calibration solution.
I calibrated the refractometer to zero with my rodi water. Put drops of calibration solution on it and it still reads zero.
Mixed 4 gallons of water 1/2 cup per gallon and test. Reads just shy of 35ppt.
So I'm guessing I have a bad calibration fluid. I also reversed the test also. Calibrated at 35ppt with the fluid and then tested rodi water. It read 35ppt!.

so now the question is if your water your are making was off, what is your tank reading at? Bring your refractometer to your LFS and ask them to calibrate it. then check your tank, the water your testing and your calibration solution.

 

[Joel j]

The TDS of the calibration solution will be around 35,000 ppm your tds meter will not be able to read it.

Sounds like you calibration solution is water.

Exactly! It was only 250ppm

 

[Joel j]

so now the question is if your water your are making was off, what is your tank reading at? Bring your refractometer to your LFS and ask them to calibrate it. then check your tank, the water your testing and your calibration solution.

The tank is about 3/4 full at this time. I'm gonna have to use the refractometer calibrated with rodi to test.
The water in tank is just above 20ppt.
There is no local fish store to help me me. Nearest local wish marine is 3 hours drive..... I live in the woods.

 

[VintageReefer]

so now the question is if your water your are making was off, what is your tank reading at? Bring your refractometer to your LFS and ask them to calibrate it. then check your tank, the water your testing and your calibration solution.

Tank is being filled for the first time

 

[Joel j]

That is correct

 

[PastaReefs]

I always check chewy, sometimes Petco runs clearance on the salt too. I also check the discontinued section on brs sometimes you can find a steal there.