How did I ever go without a refractometer?

[LowCel]

I just received my refractometer from hoopsguru over at www.reefnut.com , this thing is awesome. I can't believe that I actually had a tank as long as I did without one. I have always used a Coralife Deep Six hydrometer. I knew it wasn't perfect but when I compared it to Matt's refractometer about 9 months ago it was .002 off. I just always took that into account.

Anyway, I just finished testing my water.

Hydrometer reading - 1.020
Refractometer reading - 1.025

That is quite a difference. If I would have been showing 1.025 on the hydrometer my water would have actually been 1.030.....in other words everything in my tank would have been dead!

It was well worth the $39.95! If anyone is interested he still has a few. I have seen them for a couple of bucks less other places but personally I would much rather help out a friend. Plus he has a cool little forum going on and he is always more than willing to help out a fellow hobbiest.

Just please do me a favor and let him know that I told you about him.

[Shikaroka]

Forgive my ignorance, but do you really need to be that accurate?
How do you know which one is more accurate?

[Highlander]

Because you can calibrate a refractometer

[Shikaroka]

Originally posted by Highlander
Because you can calibrate a refractometer

That makes sense.

[firefish2020]

I still like my pinpoint, been using it since about a week after setting up our tank, I hate swingarms.

[MattG]

if you are using a swing arm id highly suggest you check it against a reliable source such as a refractometer or salinity monitor. if anyone needs me to bring my refracto to the next meeting id be more then happy to check anyones hydrometer. its really surprising the different readings hydrometers give.

[firefish2020]

Matt why dont you bring it anyway, I think people are just not shure about other salt monitoring eq. out there. I'll bring my Pinpoint also, might be a good topic for a duscussion at the meeting.

[Shikaroka]

Yes, good idea.
I've seen the pinpoint in action, but never a refractometer.

[MattG]

hey bruce you should bring yours too. then we can compare ours against each other and see just how accurate they are.

only one ive ever compared mine against was playfairs when he sent us the first shipment of frags.

[LowCel]

I can do that.

I can also bring my tds meter if people would like to bring in a sample of tap water just to show how many contaminents are being added to their tanks with every water change. Just a thought.

Matt, could you bring yours too so we can compare them as well?

[MattG]

sure thing.

[coralreefer]

Don't know how I missed this earlier. I've often thought this would be a good topic for the club. Anybody thought about making a salinity standard for this comparison? Randy has a recipe for one somewhere.

Surprising enough my old Deep six hydrometer was pretty accurate. Calibrated with a standard and later comparing it to a refractometer a reading of 1.025=1.024.5

[firefish2020]

Funny thing is the old Deep six we used at work was very acurate, I say used because someone apparently took it a week or so ago. Now we'll never find one that accurate again.

[hmott]

what salinity would be needed? The company I work for owns an analytical reagents company, and I have access to all the data points. These are certified reference material used in 100+ lab round robin verification tests :) I just don't know what salinity would be needed, then I'll have to check if we have one at that salinity thats been through a round robin. If so I'd be happy to bring it. It would then be your monitor against 100+ nationally (nelac) certified laboratories.

[hmott]

I just did a quick search and they are in PPT (parts per thousand) and I have no idea how to convert them. they seem to range from about 3 ppt to about 10 ppt with most in the 3 - 5 range. Oh that reminds me, we also have certified reference materials for pH, total desolved solids, total suspended solids, total solids, ammonia, nitrogen, etc. If we wanted to check anything else against reference materials just let me know and I'll see if we have something that fits.

[LowCel]

hmott, do you have access to a ph sample that is 8.0 or close to that? I would like to compare my ph tester to it if so.

[hmott]

7.80920
7.98496
8.03019
8.22402
8.46103
8.61027
8.61819

thats between 7.8 and 8.8 in our system, but I can't check if its on the shelf from my desk. but with two really close to 8 I should be able to find one of them. First I'll see which one had better interlab results in case we have both.

[LowCel]

Wow.......those are definately a lot more accurate than I need. Mine only goes to the tenths postion. :)

Exactly what is it that you do that needs that kind of accuracy????

[hmott]

We make analytical standards or (tight tolerence analyte reagents).. err well that company does. The parent company that I work for does proficency testing and data analysis for laboratory certification. Basically if you want to tell the world "I test [analyte] for $xx send me a sample and I'll tell you how much [analyte] is in it." then you need to be certified to do that. There are state, federal and 3rd parties that certify your lab and they require you run PT samples from places like us. So we get certified that we can make the samples you use to get certified. Sounds confusing but basically we make a sample and send it to laboratories. They test it and send back the results. If they are "close enough", generally 3 standard deviations from the mean, then they get certified to do that testing commercially. If they aren't they lose their certification. In most cases a certification allows them to do business, so its taken seriously. Anyway thats basically what we do. We have about 1300 analytes that get tested in any given study by different labs and we also compair each lab against each other. It can be pretty strick stuff, we use SPDI, super pure dionized water, for our samples. I've been told you can't drink it or it could kill you. They said its so pure it would suck the ions out of your body by osmosis and eventually kill you.

[LowCel]

Uhhh, well alrighty then. Now that you have explained it it is pretty much clear as mud. j/k, sounds like a pretty good job.

BTW, are you using the spdi in your tank yet? :D

[coralreefer]

Harlan
You need to look for something around 35 ppt.

Here are a couple of links to diy versions:

Homemade Standards (http://reefkeeping.com/issues/2004-06/rhf/index.htm)

Salinity Standards (http://archive.reefcentral.com/forums/showthread.php?threadid=65509&highlight=salinity+standard)

and one on
hydrometer accuracy (http://archive.reefcentral.com/forums/showthread.php?threadid=143914&perpage=25&highlight=salinity%20standard&pagenumber=1)

Just 'cause it came up in the search :)

[hmott]

na I don't what to lug the water from work to my car, then into the house and to the tank. :) I've thought about it, I even asked if it would be ok when I started my tank, everyone said heck ya.

[hmott]

Everything we have is in the 3 to 5.5 ppt range so that isn't going to work for salinity.