thincat
Aquarium Advice Addict
- Joined
- Nov 7, 2008
- Messages
- 5,330
I want to know how you all care for your Refractometer.
Cleaning:
calibration:
and overall care.....
Cleaning:
calibration:
and overall care.....
All you've got to do to calibrate it, is only put a drop of water on the glass part, then close the sunlid and make sure it spreads all the water out on the lens. Then use the screwdriver it came with, and see that little black dot on the top? That rubber piece comes off and there's a small hole in there. After you put the screw driver in there, look into the eye piece and turn the screwdriver until the white line is exactly at 0. Wa-la you've calibrated it. But like roka said, either do this with ro/di water or with calibration fluid. I practiced calibrating mine with regular water, so thats why i know how to do it.
Yes, while you can use RO water to calibrate it, it will be calibrated for SALTWATER, not SEAWATER. If you calibrate with RO, to get a true reading of 35 ppt for SEAWATER, your refracto should read 36.7 ppt.As for calibrating it, if you don't have the calibration fluid (which personally i think is a complete waste of money and a scam.), you can just use RO water.
If you calibrated with RO, you are off by aprox 5%. If you want to be at 35 ppt and you calibrate with RO, your refracto should read ~37 ppt. If you are showing 35 ppt, you are actually at ~33.3.Well then, would my salinity be incorrect right now? And would it be off by one point? And if so.. then everytime i measure the salinity, should i subtract or add that extra point that you stated before? Or am i getting in to a whole new ballgame with those questions..
If you calibrated with RO, you are off by aprox 5%. If you want to be at 35 ppt and you calibrate with RO, your refracto should read ~37 ppt. If you are showing 35 ppt, you are actually at ~33.3.
From the article I linked to...
A 35 ppt sodium chloride solution (3.5 weight percent sodium chloride in water) has the same refractive index as a 33.3 ppt seawater solution, so the error in using a perfectly calibrated salt refractometer is about 1.7 ppt, or 5% of the total salinity.
What is more important? SG or salinity? What would be an optimal salinity level?