Refractometer vs Salinity Monitor

[alrha]

Any opinions on the accuracy of a Refractometer compared to that of a Salinity Monitor (such as the pinpoint)?

 

[barebucta]

Hey Albert,

I can't account for the Salinity Monitor b/c I havn't used one, but in my opinion a refractometer works pretty good as long as you calabirate and check t properly every now and again. Not to mention that it's a hell of a lot cheaper.

 

[alrha]

the monitor is only about $100, refractometers can be in the price range as well.
how often does it need to be calibrated? the monitor also should be calibrated say every 6 months or so.

what makes the monitor easier is all you need to do is flick a switch and see a digital readout of the salinity, but i am wondering if it is as accurate as a refractometer, or if it can suffer from interference and the like.

 

[inkblue]

i need to re-caLibrate mY refractoMetro... :happysad: coZ mY plastic tHingy is giVing off hiGher readiNgs...

 

[barebucta]

$100? didn't know they were that cheap, thought theywere like $200+, but then again I was thinking of a calcium monitor. Like I said before I have no problems with the refractometer and I am a firm believer in if it's not broken then don't try to fix it.

 

[cobysreef]

didnt they come out with an all in one moniter that reads salinity, alkalinity, nitrate, nitrite, PH, temp, ammonia, phosphate ect. I remember someone said it was like $600. I would buy one if you figure how much those test kits are.

 

[fritz]

Slama and I both found that our Swing arm hydrometers EXACTLY matched the results of our hydrometers. That being said I always feared buildup on my swingarm that would (over time) throw off the results. Calfo or one of the wetwebmedia guys did a test with their club. Everyone brought in their old swingarms and they tested all of them. They were all just about dead on.


Edit: Oh salinity monitor, sorry didn't drink coffee yet this morning. Never mind my post then.

 

[alrha]

i need to re-caLibrate mY refractoMetro... :happysad: coZ mY plastic tHingy is giVing off hiGher readiNgs...

how do you know the readings are off BEFORE you calibrate?

i always worry that if the readings are getting skewed, i may be gradually increasing/decreasing my salinity w/o knowing it.

 

[alrha]

Edit: Oh salinity monitor, sorry didn't drink coffee yet this morning. Never mind my post then.

wake up and smell the coffee :lol:

 

[cali_reef]

Albert,
My experience with conductivity meter is horrible, I think pecan also don't like his. Mine is part of my ACIIIpro which I set up to alert me when things go wrong, the probe goes nuts about 7 days after each calibration and I get an email every few minuets while at work. Now the prob is turned off altogether.

Refractometer is very accurate, you can calibrated by using RO\DI water to read zero and the 53us standard to get 1.025sg. I check my tank water at each water change and when I get new fish(to compare the water in the bag).

 

[cali_reef]

didnt they come out with an all in one moniter that reads salinity, alkalinity, nitrate, nitrite, PH, temp, ammonia, phosphate ect. I remember someone said it was like $600. I would buy one if you figure how much those test kits are.

I would like to see that, do you have a link?

 

[alrha]

Albert,
My experience with conductivity meter is horrible, I think pecan also don't like his. Mine is part of my ACIIIpro which I set up to alert me when things go wrong, the probe goes nuts about 7 days after each calibration and I get an email every few minuets while at work. Now the prob is turned off altogether.

Refractometer is very accurate, you can calibrated by using RO\DI water to read zero and the 53us standard to get 1.025sg. I check my tank water at each water change and when I get new fish(to compare the water in the bag).

yeah, when you told me my salinity was high, i got worried that my Pinpoint monitor might not be as reliable as i have come to expect. ( :thanks: for notifying me btw as i put an algae blenny and clown tang from petswarehouse in there that night)

which refractometer do you use?

 

[cali_reef]

which refractometer do you use?

Don't know the brand, it was $25 and I got it few years ago in a CALI group buy streight from China.

 

[alrha]

Using Conductivity To Measure Salinity
Randy Holmes-Farley Ph.D.

and on RC he finds the monitors to be "at least as accurate as a refractometer" plus it "can give real time measurements if you are acclimating new purchases"
http://reefcentral.com/forums/showthread.php?s=&threadid=849634&highlight=Captive+Purity+Refractometer

 

[alrha]

Russ, you still like the captive purity?

I've used the refractometers you've got posted here. They are very difficult to read. The Captive Purity Refractometer is a bit more expensive, but every person I've ever let see mine, compared to theirs has commented how precise the readings are. Unless you've seen them side by side, you cannot possibly understand how clear the Captive Purity is.

 

[pecan2phat]

IMO, the PinPoint Salinity monitor is not a worth while investment. You need to calibrate it every 30 to 60 days for it to be accurate. The norm is for the probe to read lower than the actual salinity if not calibrated. Refractos hardly need much adjustments.

I use my PP monitor as a reference since it's constantly submersed in my tank but I use my refracto for actual measurements.

 

[alrha]

IMO, the PinPoint Salinity monitor is not a worth while investment. You need to calibrate it every 30 to 60 days for it to be accurate. The norm is for the probe to read lower than the actual salinity if not calibrated. Refractos hardly need much adjustments.

I use my PP monitor as a reference since it's constantly submersed in my tank but I use my refracto for actual measurements.

i think i'm gonna be doing the same

 

[alrha]

Using Conductivity To Measure Salinity
Randy Holmes-Farley Ph.D.

and on RC he finds the monitors to be "at least as accurate as a refractometer" plus it "can give real time measurements if you are acclimating new purchases"
http://reefcentral.com/forums/showthread.php?s=&threadid=849634&highlight=Captive+Purity+Refractometer

ok, found another thread and found that Randy was not using the [relatively] cheap pinpoint monitor but rather the [more] expensive orion monitor. http://reefcentral.com/forums/showthread.php?s=&threadid=530030&highlight=Captive+Purity+Refractometer

 

[herman]

I have the pinpoint salinity monitor in the sump constantly. And once a week I doule check with a refractometer. The salinity monitor works fine for just over a month without calibration and then it starts to show lower readings than actual.

Is it a worthwhile investment? Not really! But a convenient thing to have .

 

[alrha]

Few people using refractometers have actually tested to see if they are accurate. They just assume that they are by calibrating with fresh water. That is not enough, IMO. Folks should at least once check with a higher salinity fluid matching NSW. Some folks have then been not so happy with the refractometers when performing such a check.

You cannot use a salinity standards intended for conductivity meters to calibrate refractometers.

anyone know where to get refractive index standards (other than RO/DI) to calibrate a refractometer at levels closer to what we would be testing at?