Refractometer owners

[reefrunner69]

How often do you calibrate your refractometers? I just got one yesterday, the paperwork said it was callibrated before it left the factory, and when I got it, it was off a bit. I recalibrated, and tested my tank water, the deep six hydrometer said it was a hair over 1.025, but the refractometer said it was 1.028. so I have started lowering it a bit at a time and testing with the refractometer. So that got me thinking, what impacts the need for recalibration? I assume any jolts to the instrument or possibly large sudden temp changes, but what else, and how often do you need to calibrate when it sits in a box on your desk?

Another question, All the light fixtures in my house use low wattage bulbs, that do not facilitate reading the refractometer (probably shoulda got the one with the light), works great outside though when the sun is shining. What is the wattage of the bulb you point it at to get a good reading? I suppose I could just get a little closer to the light or open the canopy and point it at the MH, but it would be a lot easier to buy a cheap walmart lamp and use it.

 

[snapcrackler]

I have an RTC10 that I checked with distilled water when I bought it and it was right on 0. Since then it has stayed on 0. I have checked it a few times and I bought it a few months ago. Still 0.

Maybe your deep 6 is just off a lil sice it is a swingarm (dont throw tomatoes at me, I dont think the deep6 is a bad unit LOL)

That's of course assuming thet the RTC10 is the accurate one out of the two, I would be inclined to think that is the case. Did yours measure 0 with distilled water when you took it out of the case the first time?

I think it would be worth it to talk to a salinity refractometer engineer type person to find out "why" it would need to be calibrated at all, outside of temperature changes. Does it matter if it gets bumped? etc.

I think I will put that on my list of TTD because now I am all curious.

 

[jamal-188]

I also have the RHS-10ATC and actually think temperature is not supposed to affect the reading. I just got mine yesterday and checked the calibration with RO/DI water and it was right at 0. My Aquarium Systems swing arm read 1.025 and my refractometer read 1.028 so I have to begin adjusting down assuming as snapcrackler stated that the refractometer is more accurate.

I was curious too why or when it would need to be re-calibrated. The only thing I can really think of is it's bumped rather hard. The readings are determined by the light refracting off the lense and it's not likely that the lense would be knocked out of alignment...

BTW, I'm sure what unit you have but my 60watt ceiling lights seem to light it up good enough to read.

 

[cj10488]

I was calibrating mine daily but that was due to the first one being broke.. i went with the Premium Aquatics Refractometer - RHS-ATC-10.. I just recieved my Replacement yesterday and it seems to be much better.. I would for sure calibrate it after you recieve it and once every few days to make sure that it is holding in the right place and comfortable.. I plan on checking mine if anything out of the ordinary shows up.. Such as it was at 36ppt and then I test and its at 20ppt.. Then I must check... lol... Outside of that maybe once a month if that.. FWIW Premium Aquatics stated that once a Yr is enough for calibrating it... As for the light I point it indirectly right at my halide lights on my tank.. Either that or I use the lamp that sits somwhat adjacent to the tank which has a 60w bulb.. I like using the halides best.. AS long as its not directly at it its real easy to read.. If its directly right at it it will be very hard.. I did find out that a regular 100w bulb works as well...

HTH<
James

 

[reefrunner69]

I also have the RHS-10ATC and actually think temperature is not supposed to affect the reading.

Mine is also an ATC model, I did not mean that temp would effect the reading, simply that large temp swings, like taking the unit from 80* temps to 20-30* temps might effect the optics. Not the temp of the water, but the environmental conditions the unit is subjected to.

 

[jamal-188]

Mine is also an ATC model, I did not mean that temp would effect the reading, simply that large temp swings, like taking the unit from 80* temps to 20-30* temps might effect the optics. Not the temp of the water, but the environmental conditions the unit is subjected to.

lol, I should have figured that's what you meant, it's not like the temp in the tank would be fluctuating to cause errors in the readings. However I don't think the optics of the unit would be affected by the temp unless it fogs up from temp change, but I could be wrong.

 

[BillyZ]

I've got a Milwakee ATC sumtin er other. I calibrated it once when I first got it. It was off by a bit IIRC, but adjusting is extreemly simple. I've checked it once or twice since then and it's always been spot on, so I don't think i've checked it in a while. But my goodness I love that thing!

I actually just put in a new flourecent light fixture in my kitchen and it works great. What i've found works best is if you look through the unit directly horiztonaly, and have the light source directly above the optics.

 

[reefrunner69]

What i've found works best is if you look through the unit directly horiztonaly, and have the light source directly above the optics.

I'll try that, I just used it pointed at a 40w incandescant bulb and with the end just a couple of feet away, it worked fine. LOL, helps being tall

 

[loganj]

I have the ATC 10 as well. I calibrated it when I got it with distilled water. It was off a tiny bit. I have checked it several times since with distilled water and it's right on the money. I usually use my desk lamp (2x15w fluor) as a light source.