YIKES! Distilled water dosnt calibrate a refractometer properly!

Windirmere · 04/08/2013, 03:09 PM

After Trying to figure out why my Mg was so low I found some horror stories about Refractometers calibrated with Distilled water. So I expressed ordered Calibration fluid that is laboratory made at 1.026 SG and found out im out by .006 or .007 meaning my SG is 1.020 or 1.019 @.@, All my SPS are doing great with alright growth, but I want to remedy this right away, Should I just do a water change (3gal) every other day with the proper SG? Or should i just top off with 1.026 salt water for a week if every thing is doing fine, and just check everyday to see where im at then switch back to Rodi.

Anyhow I think these pic's are about 4-5 months apart @,@ didn't realize how much things grow.

and today

jrp1588 · 04/08/2013, 03:19 PM

If things are doing fine as is, I'd just top off with salt water.

elFloyd · 04/08/2013, 03:22 PM

I would use salt water as ATO... But test SG daily.

gone fishin · 04/08/2013, 03:28 PM

I agree use some salted top off to get where you want. It is very important to calibrate with the proper solution. I would guess alot of problems could be caused by this.

Windirmere · 04/08/2013, 03:37 PM

Yep I think 9bucks for the Calibration solution probably saved me a lot of money. Also might explain why my zoa's dont seem to do so hot : \

dthorn · 04/08/2013, 04:35 PM

Just to clarify for anyone that doesn't know. It is always best to use calibration fluid in target range to maximize accuracy of a refractometer. The problem you encountered was likely because your refractometer and the majority sold in this hobby were made to measure brine saltwater not seawater. Recently, some companies like DD have started selling seawater refractometers which would not have this problem. That being said I still purchased calibration fluid since accuracy is highest when testing in same range as calibration.

If I ever have low salinity I just wait for evaporation to correct it, specially if everything is happy. Might be a problem though with a skimmer and or with dosing. Guessing topping off with salt water is no worse than me dumping fesh water in every couple days. Looks like things are doing great in your tank. If it's been off for a long time it wouldn't hurt to take some time raising it back up. Happy reefing!

Sk8r · 04/08/2013, 04:56 PM

Your reef salt water mix, if you get down to using precise measures as you would in a good kitchen, is usually set at 1.024: consult your label. And if you mix up a sample gallon and find your refractometer saying something else, that's a good clue you should get the test fluid and be prepared to use that tiny screwdriver that came with the instrument.

Be alert also, for aging tests: they have an expiration date, and you probably should write it in permanent marker so you can't miss it: a bad test of any sort can fake you into really bad chemistry.

dthorn · 04/08/2013, 05:09 PM

Although she didn't say it directly, skr made a point I was thinking when looking at your pics again after I posted. Double and triple check any test that suddenly tells you there's a big problem in a tank that looks like yours. Good corraline everywhere, clean, great color on all sps, and my limited experience can't judge your growth but looks pretty decent. Make very sure that you didn't just get a bad bottle of calibration fluid.

Windirmere · 04/08/2013, 05:36 PM

Nah the fluid is correct, Just back from the LFS to test against their refractometer. My dumpie back up swing arm was useless as ever, I could tap it to what ever I wanted to see :\.

The salt im using is H20 ocean, the pale sayed the mg should be at 1300-1400, and that was the 1st red flag for me. My Elos test kit was saying only 800-900 Ppm on multiple tests. I have a new batch brewing and im hopping to see higher Mg at the real 1.026 SG.

Another quick question, Can refractometers fall out of calibration? Should I just get into the habit of ordering new calibration fluid every 6moths (just in case water evaporates from this little container in the mean time)?

jrp1588 · 04/08/2013, 05:40 PM

Keep the container sealed and it won't evaporate.

disc1 · 04/08/2013, 06:04 PM

Quote:

Originally Posted by Windirmere

Nah the fluid is correct, Just back from the LFS to test against their refractometer. My dumpie back up swing arm was useless as ever, I could tap it to what ever I wanted to see :\.

The salt im using is H20 ocean, the pale sayed the mg should be at 1300-1400, and that was the 1st red flag for me. My Elos test kit was saying only 800-900 Ppm on multiple tests. I have a new batch brewing and im hopping to see higher Mg at the real 1.026 SG.

Another quick question, Can refractometers fall out of calibration? Should I just get into the habit of ordering new calibration fluid every 6moths (just in case water evaporates from this little container in the mean time)?

They can and do fall out of calibration. Temperature can also have an effect. It is a good habit to throw a little calibration solution on there once in a while for a check.

If you have access to a good balance, there is a DIY solution to the calibrant. A 36.5ppt saltwater will match S35 seawater exactly in refractive index. To make that, dissolve 3.65g of table salt into 96.35g of water. If you don't have that kind of accuracy on your scale, multiply both measures by ten and make a liter of it. I like to make it up fresh whenever I calibrate my refrac so I don't have to rely on a solution that has been sitting around.

Beyond evaporation, if you see any precipitation or little salt crystals then the solution is also no good.

04/08/2013, 03:09 PM	#1
Windirmere Registered Member Join Date: Apr 2012 Location: Courteny BC Canada Posts: 452	YIKES! Distilled water dosnt calibrate a refractometer properly! After Trying to figure out why my Mg was so low I found some horror stories about Refractometers calibrated with Distilled water. So I expressed ordered Calibration fluid that is laboratory made at 1.026 SG and found out im out by .006 or .007 meaning my SG is 1.020 or 1.019 @.@, All my SPS are doing great with alright growth, but I want to remedy this right away, Should I just do a water change (3gal) every other day with the proper SG? Or should i just top off with 1.026 salt water for a week if every thing is doing fine, and just check everyday to see where im at then switch back to Rodi. Anyhow I think these pic's are about 4-5 months apart @,@ didn't realize how much things grow. and today

04/08/2013, 03:28 PM	#4
gone fishin Registered Member Join Date: Jul 2011 Location: Wyocena Wi Posts: 6,936	I agree use some salted top off to get where you want. It is very important to calibrate with the proper solution. I would guess alot of problems could be caused by this. __________________ Tony Current Tank Info: 180gal DT, BM NAC77 skimmer,3 Maxspect razors, Maxspect Gyre 150, 30g QT

04/08/2013, 04:56 PM	#7
Sk8r RC Mod Join Date: Feb 2006 Location: Spokane WA Posts: 34,628 Blog Entries: 55	Your reef salt water mix, if you get down to using precise measures as you would in a good kitchen, is usually set at 1.024: consult your label. And if you mix up a sample gallon and find your refractometer saying something else, that's a good clue you should get the test fluid and be prepared to use that tiny screwdriver that came with the instrument. Be alert also, for aging tests: they have an expiration date, and you probably should write it in permanent marker so you can't miss it: a bad test of any sort can fake you into really bad chemistry. __________________ Sk8r Salinity 1.024-6; alkalinity 8.3-9.3 on KH scale; calcium 420; magnesium 1300, temp 78-80, nitrate .2. Ammonia 0. No filters: lps tank. Alk and cal won't rise if mg is low. Current Tank Info: 105g AquaVim wedge, yellow tang, sailfin blenny,royal gramma, ocellaris clown pair, yellow watchman, 100 microceriths, 25 tiny hermits, a 4" conch, 1" nassarius, recovering from 2 year hiatus with daily water change of 10%.

04/08/2013, 03:19 PM	#2
jrp1588 Registered Member Join Date: Nov 2009 Location: Evansville, IN Posts: 1,864	If things are doing fine as is, I'd just top off with salt water.

04/08/2013, 03:22 PM	#3
elFloyd Registered Member Join Date: Jan 2009 Location: Cumming, GA Posts: 421	I would use salt water as ATO... But test SG daily.

04/08/2013, 03:37 PM	#5
Windirmere Registered Member Join Date: Apr 2012 Location: Courteny BC Canada Posts: 452	Yep I think 9bucks for the Calibration solution probably saved me a lot of money. Also might explain why my zoa's dont seem to do so hot : \

04/08/2013, 04:35 PM	#6
dthorn Registered Member Join Date: Jan 2013 Location: erie pa Posts: 280	Just to clarify for anyone that doesn't know. It is always best to use calibration fluid in target range to maximize accuracy of a refractometer. The problem you encountered was likely because your refractometer and the majority sold in this hobby were made to measure brine saltwater not seawater. Recently, some companies like DD have started selling seawater refractometers which would not have this problem. That being said I still purchased calibration fluid since accuracy is highest when testing in same range as calibration. If I ever have low salinity I just wait for evaporation to correct it, specially if everything is happy. Might be a problem though with a skimmer and or with dosing. Guessing topping off with salt water is no worse than me dumping fesh water in every couple days. Looks like things are doing great in your tank. If it's been off for a long time it wouldn't hurt to take some time raising it back up. Happy reefing!

04/08/2013, 05:09 PM	#8
dthorn Registered Member Join Date: Jan 2013 Location: erie pa Posts: 280	Although she didn't say it directly, skr made a point I was thinking when looking at your pics again after I posted. Double and triple check any test that suddenly tells you there's a big problem in a tank that looks like yours. Good corraline everywhere, clean, great color on all sps, and my limited experience can't judge your growth but looks pretty decent. Make very sure that you didn't just get a bad bottle of calibration fluid.

04/08/2013, 05:36 PM	#9
Windirmere Registered Member Join Date: Apr 2012 Location: Courteny BC Canada Posts: 452	Nah the fluid is correct, Just back from the LFS to test against their refractometer. My dumpie back up swing arm was useless as ever, I could tap it to what ever I wanted to see :\. The salt im using is H20 ocean, the pale sayed the mg should be at 1300-1400, and that was the 1st red flag for me. My Elos test kit was saying only 800-900 Ppm on multiple tests. I have a new batch brewing and im hopping to see higher Mg at the real 1.026 SG. Another quick question, Can refractometers fall out of calibration? Should I just get into the habit of ordering new calibration fluid every 6moths (just in case water evaporates from this little container in the mean time)?

04/08/2013, 05:40 PM	#10
jrp1588 Registered Member Join Date: Nov 2009 Location: Evansville, IN Posts: 1,864	Keep the container sealed and it won't evaporate.