Refractometer needing calibrated monthly

kac01 · 02/10/2018, 08:13 AM

Can someone please explain why my two refractometers need calibrated every water change. I have two refractometers and they both get about .05 out of calibration every month. Thanks

DesertReefT4r · 02/10/2018, 08:25 AM

Try some fresh calibration fluid and .05 is not much to worry about. 35 ppt +-1.0 is good imo.

Zalick · 02/10/2018, 08:58 AM

Mine stays spot on. New one purchased a year ago and it hasn't fallen out of calibration yet. Not sure why yours does. I would think low quality?

reeftanker3295 · 02/10/2018, 09:20 AM

Mine both do the same exact thing, only realized after buying calibration fluid on a whim one day. In a week they read about .002-.005 sg low. One's off eBay and ones a red Sea, not very old. Just remember to calibrate every time you use it, takes 2 seconds.

jayball · 02/10/2018, 10:52 AM

Red sea refractometers are known for needing calibration every time you use them. The one I purchased from BRS years ago gets checked often but I only need to turn the screw once a year or so. Be sure it is not getting banged around in a drawer or something like that, they are shock sensitive.

outssider · 02/10/2018, 07:04 PM

Quote:

Originally Posted by jayball

they are shock sensitive.

they are also temperature sensitive !!... that is, the temperature of the refractometer/room temperature. try calibrating it in a cold place (let the refractometer reach the cold room temperature) then calibrate it then take it to a warm place, let it set for a while and check the calibration....

DesertReefT4r · 02/10/2018, 07:11 PM

Oh yeah temp changes the reading as well forgot about that. I would calibrate mine 2-3 times a year and never needed major adjustment.

bif24701 · 02/11/2018, 02:46 AM

I don’t calibrate mine, I can’t. Darn thing rusted and now it’s impossible. All you need to do is check it with your saltwater cal fluid and match it to your water. Easy. Even better, just match the new water to the water from display tank. I verify my display is within range once a week by comparing it to my refractometer cal solution.

Always allow 1 min to pass after you place the sample on refractometer before taking a reading.

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JoeyBagadonuts · 02/11/2018, 06:39 AM

I used to have to calibrate mine often when I kept it in a cabinet in the garage. Now I keep it in the house in a stable temperature and it stays right on. I just check it occasionally.

kac01 · 02/11/2018, 07:18 AM

thanks

ca1ore · 02/11/2018, 09:32 AM

If you meant on the SG scale, then that's a lot (1.025 versus 1.020?). Mine won't drift that much in a year. If you meant 0.05 on the ppt scale then never mind, no biggie.

kac01 · 02/13/2018, 12:13 PM

The SG scale moves that much on both refractometers.

mako61 · 02/13/2018, 01:27 PM

Mine says ATC on it, think it came from BRS. It drifts +-.001 on the SG scale the times I have checked it. no where near .005 SG.

Zalick · 02/13/2018, 05:18 PM

Quote:

Originally Posted by kac01

The SG scale moves that much on both refractometers.

What brands are you using? I've been using the Vee Gee Scientific STX-3 for about 1.5yrs now and its still on the money. Its much better than my Sybon.

HBtank · 02/13/2018, 05:24 PM

Quote:

Originally Posted by Zalick

What brands are you using? I've been using the Vee Gee Scientific STX-3 for about 1.5yrs now and its still on the money. Its much better than my Sybon.

I have had the same experience with my $30 refrac, and have seen many with similar results on cheap "ATC refracs" when I have read these threads.

No joke, touched the screw barely 2x in 13 years; my 35 ppt reference solutions are always spot on!

I think the reality is that most refracs are very solid except the red sea one, which seems to be some weird torture device disguised as testing equipment.

bif24701 · 02/13/2018, 05:51 PM

This will help you guys understand why these things are happening.
http://reefkeeping.com/issues/2006-12/rhf/index.php

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02/10/2018, 08:13 AM	#1
kac01 Registered Member Join Date: Oct 2008 Location: Kansas City Posts: 218	Refractometer needing calibrated monthly Can someone please explain why my two refractometers need calibrated every water change. I have two refractometers and they both get about .05 out of calibration every month. Thanks

02/10/2018, 08:25 AM	#2
DesertReefT4r Registered Member Join Date: Sep 2015 Location: Mesa Az Posts: 771	Try some fresh calibration fluid and .05 is not much to worry about. 35 ppt +-1.0 is good imo. __________________ Tank history 29g tropical ,55g cichlid tank, 20H softy reef, 29g mixed reef, 20H brackish goby & puffer tank, 55g mixed reef, 6g Nanocube softy lps reef, 40B sps reef, 75g sps reef, 75g sps reef in bu Current Tank Info: 75g sps reef build in the works.

02/10/2018, 08:58 AM	#3
Zalick My reef tanks my wallet Join Date: Dec 2011 Location: Portland Posts: 571	Mine stays spot on. New one purchased a year ago and it hasn't fallen out of calibration yet. Not sure why yours does. I would think low quality? __________________ 300g custom acrylic from James 72x36x27, 4 Mitras Lx7 &6 a360, 2 Stream 3s, C2C beananimal. 100g sump, Jebao DCP- 8000 (Vectra M1 died) -> 114w aquauv -> SRO 5000ext , varios8 return Current Tank Info: Me v Dinos - I'm winning for now...

02/10/2018, 07:11 PM	#7
DesertReefT4r Registered Member Join Date: Sep 2015 Location: Mesa Az Posts: 771	Oh yeah temp changes the reading as well forgot about that. I would calibrate mine 2-3 times a year and never needed major adjustment. __________________ Tank history 29g tropical ,55g cichlid tank, 20H softy reef, 29g mixed reef, 20H brackish goby & puffer tank, 55g mixed reef, 6g Nanocube softy lps reef, 40B sps reef, 75g sps reef, 75g sps reef in bu Current Tank Info: 75g sps reef build in the works.

02/11/2018, 02:46 AM	#8
bif24701 Registered Member Join Date: Jan 2011 Location: Florida, FWB Posts: 3,389	I don’t calibrate mine, I can’t. Darn thing rusted and now it’s impossible. All you need to do is check it with your saltwater cal fluid and match it to your water. Easy. Even better, just match the new water to the water from display tank. I verify my display is within range once a week by comparing it to my refractometer cal solution. Always allow 1 min to pass after you place the sample on refractometer before taking a reading. Sent from my iPhone using Tapatalk __________________ 180 Mixed Reef SRO-5000 Skimmer Neptune APEX Gold Kessil AP700/ MP60+6105 Kalk+2 part/ Cheato Fuge Current Tank Info: 180 SPS Dominant

02/10/2018, 09:20 AM	#4
reeftanker3295 Registered Member Join Date: Dec 2009 Posts: 192	Mine both do the same exact thing, only realized after buying calibration fluid on a whim one day. In a week they read about .002-.005 sg low. One's off eBay and ones a red Sea, not very old. Just remember to calibrate every time you use it, takes 2 seconds.

02/10/2018, 10:52 AM	#5
jayball Registered Member Join Date: Mar 2014 Location: Maryland Posts: 1,671	Red sea refractometers are known for needing calibration every time you use them. The one I purchased from BRS years ago gets checked often but I only need to turn the screw once a year or so. Be sure it is not getting banged around in a drawer or something like that, they are shock sensitive.

02/11/2018, 06:39 AM	#9
JoeyBagadonuts Registered Member Join Date: Aug 2014 Location: Tarpon Springs, FL Posts: 80	I used to have to calibrate mine often when I kept it in a cabinet in the garage. Now I keep it in the house in a stable temperature and it stays right on. I just check it occasionally. __________________ 75 Gallon Mixed Reef 16" Shadow Overflow, Eheim 1262, Vortech MP40, Reef Octopus 150, Coralife Aqualight Pro (2 150w Phoenix 14k, 4 54w T5ho (2 ATI Actinic, 2 ATI Blue Plus)), Hydor ATO, Jebao doser

02/11/2018, 07:18 AM	#10
kac01 Registered Member Join Date: Oct 2008 Location: Kansas City Posts: 218	thanks

02/11/2018, 09:32 AM	#11
ca1ore Grizzled & Cynical Join Date: Apr 2006 Location: Stamford, CT Posts: 17,319	If you meant on the SG scale, then that's a lot (1.025 versus 1.020?). Mine won't drift that much in a year. If you meant 0.05 on the ppt scale then never mind, no biggie. __________________ Simon Got back into the hobby ..... planned to keep it simple ..... yeah, right ..... clearly I need a new plan! Pet peeve: anemones host clowns; clowns do not host anemones! Current Tank Info: 450 Reef; 120 refugium; 60 Frag Tank, 30 Introduction tank; multiple QTs

02/13/2018, 12:13 PM	#12
kac01 Registered Member Join Date: Oct 2008 Location: Kansas City Posts: 218	The SG scale moves that much on both refractometers.

02/13/2018, 01:27 PM	#13
mako61 Registered Member Join Date: Feb 2017 Location: Dallas Posts: 359	Mine says ATC on it, think it came from BRS. It drifts +-.001 on the SG scale the times I have checked it. no where near .005 SG. __________________ Thanks, Mako Current Tank Info: Returning Reefer - Red Sea 525XL, Mitras LX7s, Apex, check homepage for vids of tank

02/13/2018, 05:51 PM	#16
bif24701 Registered Member Join Date: Jan 2011 Location: Florida, FWB Posts: 3,389	This will help you guys understand why these things are happening. http://reefkeeping.com/issues/2006-12/rhf/index.php Sent from my iPhone using Tapatalk __________________ 180 Mixed Reef SRO-5000 Skimmer Neptune APEX Gold Kessil AP700/ MP60+6105 Kalk+2 part/ Cheato Fuge Current Tank Info: 180 SPS Dominant