Refractometer

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Trogdor

New Member
I just received mine in the mail today. I ran out and purchased some bottle water that says it is filtered by RO. (I'm in the process of saving for an RO unit, i know tap is bad...) Anyway I calibrated the refractometer and tested my water. 1.033...WHOA! Ok so I figured that I screwed up the calibration so I test my tank water again...1.033. Ok back to recalibrate...1.000. Back to the tank 1.033. I have tested it like 5 times and it kept coming back 1.033. I had a float hydrometer from when I had a tank a few years back and never got around to getting a refractometer. My float was reading 1.024 throughout this whole time.

My question is, could I have really screwed something up so bad during the calibration that my refractometer would be off by that much? If you sit and think about it, any additional salt during calibration would make your actual readings lower. I don't doubt that the float hydrometer is off, but 0.009 seems like a lot for a float to be off. Another question...could this high salinity be the reason that my cycle is taking forever? My ammonia has been at 1.0-2.0 for almost 2 weeks now.

Anyway thanks for any replies...
 
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Trogdor

New Member
yes and i did wait the 30sec that it recommended during the calibration everytime that i tested the RO water and tank water.
 
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reefman23

New Member
Can you take a sample to a LFS or a friends house or something where you can get a "third-party" reading?

Jesse
 
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gparr

New Member
What is the temp of your tank and the temp at which your float hydrometer is calibrated? By float hydrometer, I assume you mean one of those glass-bulb devices, not a swing-arm hydrometer. Also assuming there are no air bubbles on the float hydrometer? I use a float hydrometer, but make my water measurements by partially filling the tube in which the hydrometer is stored and putting the hydrometer in the tube. This allows me to read it at eye level in a stationary position, rather than floating around in the tank. AFAIK quality glass float hydrometers are accurate, but I've only used the large size. I have seem smaller glass-bulb hydrometers and would question their overall accuracy.
Gary
 
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Trogdor

New Member
I'm heading to the LFS after work to have my water tested there. I'm planning on taking a cup of water and running my standard set of tests; ammonia, nitrite, nitrates & salinity before I head over. I will have them test the cup for the same that i tested it for to get a good comparison. Thanks for the suggestions.

Btw, I don't think it was the Hagen float hydrometer but it was a larger one (~12in). I will try and test the RO water that I had to see if it is close to 1.000 on it as well. It never crossed my mind to test that last night. The float hydrometer that I have just has a piece of paper rolled up inside the small tube and it has the graduation marks on the paper. Not sure how easily the paper can slide in the tube but it looks cheaply made.

EDIT: Tank temp was 79.5F I'm not sure what my float hydrometer was calibrated at. I wasn't next to the production worker that made it...lol :D :lol3:
 
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gparr

New Member
The calibration temp should be stated on the hydrometer. I have a large one, too, and it has served me well and accurately for years. It's calibrated at 77 F. If you're at 79, I'm not sure if that gives a higher or lower sg reading. I doubt it would make the kind of difference you're experiencing, however.
Gary
 
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Trogdor

New Member
Aight, I just got back and all of my parameters were right on target. The refractometer was dead on with the LFS's along with my test kits. Last night I lowered the salinity to 1.027 per the refractometer, since i have no livestock and still in the early stages of my cycle. Now the hydrometer reads 1.022 and the refracto at 1.027. I guess .005 isn't too bad for being off but I'm sure it wasn't helping my cycle much.

There was no calibration information on the hydrometer. I purchased it 2 years ago and I no longer have the information that came with it. Thanks for the help everyone.
 
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