How do you clean your refractometer lens?
 

I got a refractometer for Christmas and have been going crazy trying to trust the readings. I have the Pinpoint 35ppt salinity solution that I use to calibrate it before each test. I noticed that if I don't thoroughly rinse the lens and cover with clean (no salt) water and then dry with a paper towel it will give me odd readings. Is this what you guys do as well (clean the lens with water)? or do you just wipe it off with a dry towel or something? I'm very paranoid about getting bad readings...

The instructions just say to wipe off the lens between uses. I have this one:
http://www.drsfostersmith.com/Produc...fm?pcatid=9957

I rinse with some RODI water and wipe clean.

I usually just rinse and let air dry. I am probably too anal, but lab grade refractometers can get scratched even with kimwipes and I have gotten used to not wiping with anything like a papertowl.

+1. If you use good quality RO/DI and the unit isn't filthy, it should dry perfectly clean (i.e. no deposits.)

And to the OP, while it's noble to calibrate every time, it's probably not required. Once a month is probably fine. Try pointing at a bright light while you're taking the reading, and check to see if there's an adjustable focus on your instrument.

I will be honest.... I just wipe mine on my undershirt. :)

+1 on the shirt.

Dont use paper though, It will scratch it.

lol thought I might be alone on this.

I rinse with RO then wipe off with my shirt. Also when I go to check I dont use a drop of water I use a bunch so if anything is on the lens it will wash off with the new saltwater.

Thanks for all the replys everybody! It sounds like rinsing with RO is the important part. I did a bunch more testing today and if I don't rinse with RO I get inconsistent test results (even with the calibration liquid).

RO + Shirt here!

I calibrate with RO, tried the 35ppt and the reading was true calibrated with RO...

I agree with avoiding the paper. A soft cloth and some RO/DI water for me. If anything gets deposited, a bit of vinegar on the cloth can help. The microfiber cloths for cleaning camera lenses are perfect.

Shirt, old paper towel laying next to water barrel, what ever is handy. Just make sure it's clean when you put it away. I think the most important thing is to not go crazy trying to get it prefect. Calibrating everytime you use it is a bit extensive. Trust the law of averages and your equipment and it will come out fine.

skeeter

I dry it with my shirt LOL.

When I first started reading this thread I thought I was the only one who used my shirt.

haha, sounds like the overwhelming response is "use your shirt!!!"
I do it too

I use a clean terry cloth towel. Maybe I should switch to my shirt! :)

Kinda shocked at all the shirt comments. What the point of using RO if you just go wiping it with your shirt?! ;)

Got to love simplicity at times... I do the shirt also :spin3:

Yup. Shirt.

YEP......gotta go with the T-Shirt.

Every Refractometer that I have had says to clean the lens with a soft cloth so you dont scratch it.

99% of the time when I check the salinity.....I wearing a soft T-Shirt.

+1 this is all I doo also

Calibrating with RO water will NOT give you true accurate readings at the level we are testing. Please do not do this and think you are getting accurate results.

Make sure you shake the bottle well before using the Pinpoint 35ppt salinity solution. When my salinity started to drift down for no apparent reason I shook the bottle to mix and rechecked. The unit was in fact calibrated correctly.

Micro Fiber towel.

Even more basic: I wipe mine on the inside of my forearm, figuring towels are too apt to scratch the lens.

One more use tip: be SURE to void the collection bulb each time: if salt accumulates in it due to water left behind it can screw a reading.

Calibrating with RO or RO/DI water will not give you accurate results. I found out the hard way as I was practicing this method and over time my salinity kept creeping up b/c I was using RO/DI water to calibrate but it does not completely solve the issue. I picked up some calibration solution at my local fish store and re-calibrate every 2 weeks to ensure that i'm getting an accurate reading. I've had no problems since.