Watch your refractometer

jlaudiofreak

jlaudiofreak

New member
After racking my brain trying to figure out what was wrong with my tank with my sps RTNing, I went and saw Chris at Einstiens Aquatics today. After doing a water test Chris checked the salinty of my water, and after tripple checking he told me it was reading 1.015. My refractometer which is only 5 mths old said my salinty was 1.026. Came back home checked it with my old refractometer and it read 1.015. So to all make sure your refractometer is giving you the right reading. Got to go start slowly bringing the salinty back up
 
trying my best , I just dont want to raise my salinty up toi fast and shock them. So i will be keeping my fingures crossed over the next few day. I want to take all the sps that are not attached to my buddies house but still afraid of shocking them
 
Gotta calibrate. I'm at the point now where I check calibration everytime I do a water change. I like the Aquacraft calibration solution(BRS has it) because it comes with a dropper tip and made for refractometers. The pinpoint stuff I had didn't have the dropper tip, it may even be geared towards calibrating probes.
 
I'll third (fourth?) the advice for using calibration fluid. I know a lot of folks "calibrate" using RO water, but that doesn't actually calibrate the instrument. For any measuring instrument, you have to use something that is known to be in the range you are looking for. RO water should only be used as a secondary check.

For example, in a lab the pH probes are calibrated with three standards, 4.0, 10.0 and 7.0 for fluids that are expected to be somewhere around 7.0 and this is done on a regular basis and/or everytime something is to be tested. Since our refractometers are adjusted with a screw mechism, they do loosen over time (mine does at least) and need to be tightened, which brings the SG down, ie if the calibration fluid reads 40ppt, I tighten the screw and the reading comes down to 35ppt, where it should be.

OK, over explanation over! ;)
 
i use the stuff from BRS... 6 bucks for a bottle that would should last quite a long time... there may be a small shipping fee, but its soooo worth the peice of mind... jmo
 
Funny, I was just asking about this in another thread: How far off can I possibly be using RO? I always poo-poohed the calibration fluid.

Maybe I should inquire in the chemistry forum?
 
dixiedog said:
Funny, I was just asking about this in another thread: How far off can I possibly be using RO? I always poo-poohed the calibration fluid.

Maybe I should inquire in the chemistry forum?
Click to expand...

Calibration solution is the way to go, as somebody said above you want to calibrate in solution which is close to whatever you are testing. I don't know how far off it would be using RO/Distilled water to calibrate for saltwater. It's just not as accurate.
 
fishypets said:
Do not use Pinpoint! Not accurate at all.
Click to expand...

that is funny because i bought two different brands of calibration fluid for my
refract and they both read the almost the same. Same meaning I can barely
tell the difference and you have to be careful just to notice. If i had to pull
a number out of my rear I would say a difference of .0005ish

aquacraft is the other brand.
 
dixiedog said:
Funny, I was just asking about this in another thread: How far off can I possibly be using RO? I always poo-poohed the calibration fluid.

Maybe I should inquire in the chemistry forum?
Click to expand...

You can be off up to 7ppm --I was. +1 for getting calibration solution.
 
Three batches of new pinpoint fluid were tested and all three had different readings. You tell me how accurate it is.
 
fishypets said:
Three batches of new pinpoint fluid were tested and all three had different readings. You tell me how accurate it is.
Click to expand...

the problem with reading one or two people complain about a product is that we
never know the full story. perhaps the refract had a problem and it was broken
in some way. perhaps some of the bottles that were purchased sat in a warehouse
for years before ending up in the customer's hands. perhaps... etc..

if one is worried about this type of issue you simple order two different brands
of cal fluid and compare them. if they both read very close.. you are more then
likely in the right ball park.

i tend to trust products but i still like to verify versus another. that is probably
why i have 3 alk kits right now... sure, one is getting old, and the other is
almost gone, but it is something i can use for a sanity check against my hanna
checker.
 
You must log in or register to reply here.

Similar threads

E
Refractometer woes….what would you do?
Replies
12
Views
810
jrill
J
hrdneglcry
Why can't I grow coral?
Replies
3
Views
496
Reefing102
Reefing102
S
Its been a while.
Replies
8
Views
791
sleeperls
S
Z
New lps frags - 1 day not doing well
Replies
16
Views
950
Reefing102
Reefing102
S
High Phosphate leaching from rock - persist or replace?
Replies
2
Views
615
griss
griss
Back
Top