refractometer solition any one have any?

H

hydro

Hi all
Does any one have some, so I can check my meter. Hate to spend $10 to ship a $5 item.
Let me know or I will have to order some this weekend.
Thanks Joe
 
Use regular old distilled water, guys.


contains nothing but pure H20

Distilled water will have an SG of 1.000.


So put distilled water on your fracto, if it says anything other than 1.000, turn the calibration knob until your line is at 1.000.


Now, clean the lens, and re-test.

You are now calibrated to a known 0. Now, when you put seawater on there, and are looking for 1.023 - 1.024 , you'll know it's correct
 
I personally would use calibration fluid, but it might depend on your model of refractometer. Even DI water, made or purchased, can acquire chemical components (eg. CO2 dissolved in water created carbonic acid giving it a slightly acidic pH ~6 / the same reason why rain waters pH is 5.5 on average). And you are testing salinity at 35ppt an the calibration fluid will be closer to that rather than DI at 0ppt. I check mine with calibration fluid AND DI water just to see if it's consistent and it usually is when I do the initial calibration with the fluid and not DI.

My $0.02.
 
Woa.. Sorry.. Really old post. I need to look at dates.. This is what I get for participating in the forums :grin:

Sent from my SAMSUNG-SGH-I747 using Tapatalk 2
 
@Cameron wrote:
Woa.. Sorry.. Really old post. I need to look at dates.. This is what I get for participating in the forums :grin: Sent from my SAMSUNG-SGH-I747 using Tapatalk 2 said:
Yeah me too! I didn't even look at the dates!
Click to expand...
 
For your consideration:

If you calibrate to 35ppt and the solution is off by 1%, you'll be darn near perfect.
If you calibrate to 0ppt and the solution is off by 1%, you'll end up with a false reading that can be up to 3ppt wrong in either direction.

It's pretty important to calibrate to 35ppt, ideally at 76F. The club does offer to calibrate your refractometer at the meetings, as well as a number of other tests. I know this is a big drive for our WF members, so please do order the correct solution from your LFS or online, or learn RHF's recipe to mix up your own calibration solution. His recipe makes 2-liters of the stuff, even though you only need a few ml per session; that's just how it works out to get the right PPT mixture.
 
You must log in or register to reply here.
Top