Great Deal....Refractometer

Great price...

Always good to have a spare about to periodically confirm calibration of other...

If you don't have one...This should go to top of shopping list.

 

As promised, an update (slightly long as I kinda ramble on sometimes):

I got my refractometer a couple of days ago. Here's how it went.

Tested salinity with Hydrometer: 1.025 on 38 gallon tank, 1.022 on 20 gallon tank.

Tested salinity with Refractometer: 1.025 on 38, 1.022 on 20.
WOW! Looks pretty good. But wait...........

Read instructions that came with Refractometer. DOH! Didn't calibrate it before using it. Stupid, stupid, stupid.

Didn't have distilled water, so made my own in the kitchen. Yeah, I'm a dork (still know how to distill water from college Chemistry class). Used distilled water to calibrate Refractometer. Off by .003.

Rerun tests: New salinity of 38 (1.028 ) and 20 (1.025). Oh oh, better get that 38 gallon tank down a little.

After lowering salinity by replacing some of the saltwater with freshwater, I decided to recalibrate the Refractometer again. Since I missed the part about "You must use distilled water at 68 degrees for calibration", I needed to do it again. Used store-bought distilled water, as I don't completely trust that my chem-lab (kitchen) is not putting contaminants in the water.

OK, how to get the temperature in the house to 68 degrees? AC won't get it that cold in August. Well, mothernature cooperates as we have 36 hours of "cool" weather here in NY (72 during the day and 58 during the night). With heat off, and doors/windows open, I get the house down to 69 degrees. Close enough. Recalibrate Refractometer. It's was .001 high. Rerun tests.

Newest salinity tests with Hydrometer: 1.022 on both tanks.

Tested salinity with Refractometer: 1.024 on both tanks.


SO, the Hydrometer was reading .002 low. Real salinity was 1.024, not 1.022 as I always thought it was.


Get a Refractometer people. Lord knows how far off your Hydrometer might be.

 

Every time I read one of these post , I see dollar bills flying out the door [LOL]. I guess I need one of these also.

 

If you need distilled water in the future, boil a pot of water with a lid, and remove some of the condensate from the lid of the pot.

 

That's pretty much what I did. Except my 4 cup measuring cup fit right over the top of the pot instead. Was much easier to pour that way. Still, there could be particulate matter on the glass (as it wasn't rinsed with distilled water), so it's possible I was introducing contaminants into the home-made distilled water. That's why I decided to use the store-bought distilled for the final calibration (hoped their distilling process was cleaner than mine).

 

$31.50 is all it cost (and that includes shipping).

 

Good price.

Refractometer an absolute MUST for any serious, long term, SW hobbiest!!!


Don't have - get one!


8)

 

You'll get used to that!! This is not a cheap hobby. :-/

 

After looking at the units advertised I note that the scale says 20C. Has anyone tried one of these at different temperatures and is there much difference?

 

Yea, I know--