refractometer owners

[reefrunner]

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.

[Curtswearing]

refractometers will read 1 point too high when they are calibrated at the factory. Boomer has the info so I will go searching for that info for you.

I haven't calibrated in 3 months and things seem good. I actually point at my MH lights and can read fine or go walk by a window.

[Craig Manoukian]

Will be getting a refractometer in the near future. Need to follow along so I can hit the ground running. Thanks

[Curtswearing]

More than you ever wanted to know about SG can be found HERE

[Tasslehoff]

I have not had to re-cal mine since the first time nearly a year ago. I do check it, from time to time, against base water and even some known quantities from my other hobby of home wine making.

FWIW I was never able to get it to give the same reading as my two pendulum meters. Time has shown the pendulums were both wrong.

Tass

[captivereefs]

They will be afected by temprature change also. Milwaukee makes one that automatically compesates for temprature change.It is called the ATC option. They make one with it and one without it.

[RanRoc]

I recal. mine (or check it with distilled water) every two or three months.
-RY

[Mary]

RR,
I haven't done that for months and will check mine tonight, now that you reminded me. I take a reading off the tank lights or the window light, as Curt mentioned.

[Pro_builder]

I check mine every 3 months, but haven't had to recalibrate it since I first took it out of the box. (New)
I use a 40 watt desk lamp from walmart to read the levels, works good and cost about 5.00

[SZHTTM]

I check mine about every 6 months or so. Only had to make one minor adjsutment when I first purchased it. None since and it is about 1.5 years old now.

I don't have low voltage lights in my house, so ambient light in the room is enough to make the readings.

Good Luck;

[BoomerD]

I've had mine for almost a year, and have never calibrated it. I know, I should do it. I have checked it against my r.o. water, and it's within .002 of right on, but I should get some distilled water & do it right.

[ReefLady]

Hmm .... I've only ever calibrated with RO/DI. Usually do it about every 3-4 months, usually when I calibrate the pH monitor.

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?

I'm not exactly sure what would "prompt" recalibration, other than just accuracy is lost over time in general. I know that nothing "disrupts" our pH monitor, but the readings do get a bit out of whack every few months.

What is the wattage of the bulb you point it at to get a good reading?

I'm no help here, I test the water from the sump in the basement - frag tank w/VHO's sits right next to it. Plenty bright. ;-)
If I remember right though, I have used the NO shop light on the 'fuge, and that seemed to work fine as well.

[jimeluiz]

Thanks for reminding me!!

[Gina]

We have had ours for several months. We check it occasionally and have only had to calibrate it once.

As far as lights go we use our light in the kitchen which is a 60 watt light.

[mojoreef]

Wow now I really feel like a geek. I calibrate mine everytime I use it, lol


Mike