refractometer confusion

[Zer0.]

Ok so when i got my refractometer its instructions said to calibrate it to 0 ppt with rodi water, which i did. The other night i got some 35 ppt calibration just to double check it and it was quite a bit off. I thought I had my salinity at 1.026 but after adjusting with the calibration fludid it looks like it is setting at 1.029. Every thing looks happy tho. (zoas, hammer, snails, shrimp, crabs and clownfish. now when i look at rodi water with refractometer it says my 0 tds rodi is about 7 ppt.

Not sure what to believe. Is this normal?

 

[bundybear1981]

With refractometers it is best to calibrate with 35ppt solution. The further from the calibration point the more likely for errors to occur (shift in reading) Although you are on the high side, stability is key.

 

[Vinny Kreyling]

Stick with a solution near what you intend to measure.
We do not have freshwater tanks.

 

[fishchef]

Use the solution 35%

 

[Zer0.]

Ok, thanks for the responses guys.

Just seemed weird that rodi wouldn't come up as zero (as i mentioned it was actually a good bit higher)

Guess ill just start slowly bringing my salinity down until its measuring about the same as the 35 ppt solution.

 

[scott71]

Did you calibrate with RO/DI water?