salinity

[speedstar]

Ok just tested tonight with my refractometer it tested at 1.031, this didn;t make sense as my sump levels and all correlate to 1.026. Perhaps I OD the Mg but still don't believe this number. I grabbed my old temp salinity bobber and it seems to read about 1.026. Does anyone know of a solution I can use to verify calibrate the refractometer. I'd like to do this with some household item or kitchen so I can measure now.

Thanks

[schminksbro]

There is a recipe on RC for making calibration fluid with table salt. I will find you a link.


Ok just tested tonight with my refractometer it tested at 1.031, this didn;t make sense as my sump levels and all correlate to 1.026. Perhaps I OD the Mg but still don't believe this number. I grabbed my old temp salinity bobber and it seems to read about 1.026. Does anyone know of a solution I can use to verify calibrate the refractometer. I'd like to do this with some household item or kitchen so I can measure now.

Thanks

[schminksbro]

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

[speedstar]

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

[Mike]

I ordered some solution on line for it. It is best to calibrate with the 35ppt solution...much more accurate than doing it with RO/DI

[speedstar]

RO/DI looks flat fine thats why i need something else. not sure i can get the measurement right for the formula online. WIll give it a go

[schminksbro]

You really need an accurate scale to make this. I didn't know if you had one or not. Meijers might have one in the cooking utensil section.


RO/DI looks flat fine thats why i need something else. not sure i can get the measurement right for the formula online. WIll give it a go

[jojo22]

Have you cleaned the refractometer lately?? If there is salt dried on it may re-enter the water you are trying to test when it re-hydrates, causing a higher reading than what you tank is acctually at

[tazzy695]

other possiblility is you say the dt salinity was high compared to sump and others is it possible that the dt is warmer due to your lights then the sump as temp can affect the salinity reading even on a refractometer

varify this also I know diyreef.com has the cal solution fairly cheap and usualy shipping will get it to ya next day

or I cant rember where you live but if you are close to a good lfs they may have cal solution that they can test it with or maby even if you are close to one of us fellow reefers that has cal solution like myself could do it that way too

[BeakerBob]

Speedstar, if you need some 35 PPT calibrating fluid, let me know when you are in town.

Just an FYI....the refractometer is measuring ALL dissolved solids in the water, not just NaCl (salt). So if you have been dosing large quantities of Mg, the specific gravity is also increasing. To demonstrate this, measure RO water, then add sugar to the RO, mix and measure again.

[speedstar]

I wonder if dosing vodka could have skewed it the time it was at 1.031. Any how I went to the LFS today that had calibration fluid for there use and borrowed some found it off by about 2 points and calibrated correctly now.

Thanks everyone.