recal refractometer for hypo?

[_E_]

Like the title says, I'm curious what others do when running hyposalinity in a QT.

I currently have a paired set of tomato clowns in QT and am lowering the salinity slowly from 1.026 to 1.009 over the course of a day. My refractometer is calibrated with pinpoint brand solution to 1.0257. Should I recal with RO/DI water to a SG of 0 or leave the calibration as is?

 

[Shane Hoffman]

Cal it with the solution.

 

[ataller]

What I did was I diluted my calibration solution in RODI.

A 1:1 mix should half the sg. So I calibrated my refract to 1.013, which seemed pretty close to 1.009.

Not sure how accurate this is, but its an idea...

 

[dcombs44]

You may see if you can order various calibration solutions at different SGs. Shouldn't be too expensive, then you can tell how far off your refrac is at different points.

I must have a decent one because I used Randy's solution to calibrate to 1.026 SG and my RO/DI sits right at 0.

 

[Kweli]

From what I have read.. best way to calibrate is to

1) Calibrate it to 0 with freshwater (RO or RO/DI)
2) Verify the calibration with a calibration solution. If this is correct then you are good to go. Re-calibrate every month using step 1, step 2 no longer nessesary if it passed the first test