Refractometer Qs

D

dela

Premium Member
I'm about to purchase a refractometer. Just curious if they are a pain to deal with. Do some come pre-calibrated? How often do they need to be calibrated? Seems like a poorly calibrated refractometer might be worse than a regular hydrometer.

Any comments would be appreciated.
 
I have been using my refractometer for over a year. It is easy to calibrate and I check it once every two months. I have yet to have to recalibrate it.

I suggest to anyone thinking about buying to get it. It really puts the guessing aside. With hydrometers aI never really felt that they were accurate.
 
I have been using my refractometer for over a year. It is easy to calibrate and I check it once every two months. I have yet to have to recalibrate it.

I suggest to anyone thinking about buying to get it. It really puts the guessing aside. With hydrometers aI never really felt that they were accurate.

Do you know that your refractometer is accurate, aside from being able to show that DI water matches DI water?
 
I need DI? Awww crud!

I don't use DI! :(

Been using a 3-stage RO with out too many problems. TDS~15 if memory serves. My reasoning was always that the food I put in the tank would add more stuff than the lack of DI ever would. And since I've started using lime water as make up water, I figured that helped make my make-up water purer.

I've always exported large amounts of macro, it's never been an issue.... until recently.

How important is DI in general?

But I digress...

Calibrating every time you use it does not sound fun. How do they get out of wack? Is that only the cheap ones?

Do you know that your refractometer is accurate, aside from being able to show that DI water matches DI water?
Click to expand...

What is the answer? Personally I would have no idea. Printing your article now for night time reading.

My refractometer is scheduled for delivery on Friday. At $40, it is the cheapest one I could find. I'm sure it will require lots of maintenance. :D
 
Been using a 3-stage RO with out too many problems. TDS~15 if memory serves.

That is fine. Calibrating is easy, and if it never moves, then don't bother redoing it every time. If it needs adjustment frequently, keep doing it every time.
What is the answer? Personally I would have no idea.

Exactly my point. Huge numbers of reefers assume they are accurate, and claim so in endless posts. But they do not know unless they actually check something akin to NSW. When that is done, not all are perfectly accurate.
 
Maybe I'm confussed here, but wouldn't you want your 1.000 standard setting to match the actual water you will be using. For instance, I use tap water in my tanks why would I calibrate it to DI if I'm not using DI. I know tap water is the vile nector of satan but the area I live in has good tap water. I got a report from the Water department and other than chlorine nothing special is added. Has worked well for years with no issues. I do plan to get an RODI unit tword the end of march but thats not because I'm unhappy with the tap water, but more or less to please the wife who has her opinion on whats needed for the tank as well... ;)

So since I am using tap, shouldn't I calibrate to tap?
 
<a href=showthread.php?s=&postid=6536266#post6536266 target=_blank>Originally posted</a> by kbmdale
Maybe I'm confussed here, but wouldn't you want your 1.000 standard setting to match the actual water you will be using. For instance, I use tap water in my tanks why would I calibrate it to DI if I'm not using DI. I know tap water is the vile nector of satan but the area I live in has good tap water. I got a report from the Water department and other than chlorine nothing special is added. Has worked well for years with no issues. I do plan to get an RODI unit tword the end of march but thats not because I'm unhappy with the tap water, but more or less to please the wife who has her opinion on whats needed for the tank as well... ;)

So since I am using tap, shouldn't I calibrate to tap?
Click to expand...

I know the darn thing needs to be calibrated, but my husband won't stop arguing with me about WHAT to calibrate it with! He thinks that he should calibrate it with tap.

Thanks,
Brianna
 
The refractometer is designed to be calibrated with something that has a refractive index exactly matching pure water. Many tap waters are fine. Even those with the highest salinity are typically below 1 ppt salinity, so the error introduced would be 1 ppt or less. Not enough to get worried aobut.

But it is not more correct to use tap water for calibration if you use tap water for making the salt water. That implies that ions coming in with the tap water somehow should not be "counted" as part of the final salinity, when in fact it is mostly the same ions anyway. IOW, you are not trying to determine how much the salinity or specific gravity rose on adding the salt, but what the final level actually is.

but my husband won't stop arguing with me

We may never be able to solve that problem. There are other forums for that. :lol:
 
Thanks randy. I still need to follow your recipe for NSW to determine that I am getting an accurate reading. Correct? This will give me a general target to aim for.
 
Thanks randy. I still need to follow your recipe for NSW to determine that I am getting an accurate reading. Correct?

That would be my suggestion, yes. It is useful if only to weed out radical manufacturing problems. :)
 
<a href=showthread.php?s=&postid=6545296#post6545296 target=_blank>Originally posted</a> by Randy Holmes-Farley
But it is not more correct to use tap water for calibration if you use tap water for making the salt water. That implies that ions coming in with the tap water somehow should not be "counted" as part of the final salinity, when in fact it is mostly the same ions anyway. IOW, you are not trying to determine how much the salinity or specific gravity rose on adding the salt, but what the final level actually is.
Click to expand...

Thankyou Randy, guess he just needed to hear from someone else.

<a href=showthread.php?s=&postid=6545296#post6545296 target=_blank>Originally posted</a> by Randy Holmes-Farley
but my husband won't stop arguing with me

We may never be able to solve that problem. There are other forums for that. :lol: [/B]
Click to expand...

Really? where? :lol:

Brianna:rollface:
 
Salinity calibration fluid really inexpensive to buy and even cheaper to make your own.
http://www.aquariumguys.com/salinityfluid.html
http://www.bigalsonline.com/catalog/product.xml?product_id=29809;category_id=3821
Why not calibrate your refractometer to 1.026 or whatever you want your tank to be at? Calibrating to 1.026 is the best way to get good refractometer readings. IMO there is just no good reason ,in terms of money or time savings, to calibrate with RODI vs. a trustworth calibration fluid that is closer to your target salinity.
 
I agree, although one has to be sure that it is an appropriate fluid for the device. Conductivity, refractive index, and specific gravity standards that match 35 ppt NSW may be different for all those devices. The only claim is that they meet the requirements for the device in mind,not all other devices. So a conductivity standard is not necessarily appropriate for a refractometer.
 
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