Refractometer help...

[Riotfishdude]

Hi guys,just picked up an RHS 10atc model.....

the unit says it is calibrated to 0 when shipped,i used a couple of drops of bottled spring water and got a SG reading of 1.004,then with tap,same reading,then with tap i boiled for a few minutes,same reading,then tested tank water 1.027,tested tank water with old hydrometer 1.022,should i think of the refractometer as accurate (not against the hydrometer as i know the refractometer is more accurate,but wondering why the reading of SG with the plain water used),or should i adjust that 1.004 reading down to 0 and then consider my tank readings to then be accurate,i already adjusted it down to 0 and now am getting a tank water reading of about 1.024.....Thanks again...

 

[wombat1]

Spring water probably isn't 0, for one thing, and tap water definitely isn't. You should spring for some distilled water from the store, and calibrate it to 0 with that. It's also important to let the water sit on the refractometer for awhile to equalize temperatures. The SG is fairly temperature dependent, so you need to follow the instructions specific to your instrument.

 

[Riotfishdude]

Thanks,our tap water here in Ontario is very good,after using tap,then RO i am back to using tap as there is no difference (tap contains no phosphates,nitrates etc..,this is a FOWLR tank and i run an Aerofoamer,no algae's other then coraline,no cyano's,fish all healthy for a couple years) and RO is a pain for me,i understand that water over there is not very good in comparison.....

In talking with the manufacturer,he said to calibrate my unit in accordance to my source water,the calibration of the unit can change due to shipping,adjust it to 0 with the water i will be using for my tank,then consider my tank readings as accurate as it contains the same source water,no sense comparing the readings to water that i dont use in my system,makes sense......Riot....

 

[reefsnreptiles1]

no sense comparing the readings to water that i dont use in my system,makes sense

Actually it does make sense. Generally speaking you do not calibrate instruments using water/fluids from your systems. Take ph monitors for instance. You calibrate these using specific fluids that are of a certain/absolute value.

Wombat is right. You should calibrate a refractometer using RO/DI or distilled water not tap water. If you calibrate using a source that does not have an SG or salinity reading of 0 then your readings will always be off.

Brian

 

[reefsnreptiles1]

Oops. Meant to say SG of 1.00 or salinity of 0.

Thanks!

Brian

 

[Riotfishdude]

i had thought of that shortly after posting...

indeed,getting an SG reading and adjusting it to 0 could give me false readings,same source or not......

as for distilled,this is just boiled water,i boiled water and got the same reading as the tap and spring,which made me think to just adjust that reading to 0,to bad i didnt buy this when i had my RO unit..... :roll: ......Riot....

 

[Texas2Turkey]

I've see calibration fluid sold online....

For the money they're asking, if you have acess to just a tiny bit of lab equipment, you could make your own calibration solution... with almost no problems at all.... it's really very easy.


-Brandon

 

[baseman]

Distilled water and boiled water are not the same thing. Boiling water only kills bacteria, it does not remove any minerals. The longer you boil it (reduce the volume), the more concentrated the minerals become.

 

[Robin Goodfellow]

hi.
baseman is right. Distilled water is water condensated from stream (water vapor), not water heated to boiling point. It takes ~10X more energy to get distilled than boiled water.

Obviously, Riotfishdude never do any moonshining :wink:

 

[Minh Nguyen]

Just buy some distill water from the grocery (about 1 dollar per gallon). I check my Refratometer almost every time I use it because I have RO water. I have not have to adjust it in the last year.
If you buy distil water, it will be fine. Just to let you know my tap water have 330 ppm while my my RO water have 8 ppm disolve solid in it. Our tank water have about 35 ppt (or 35000 ppm) disolve solid in it.
If you use tap water and set at 0, your error is about .3-.5 ppt.

The amount of error in your reading suggest that you may not rinse what ever you use to obtain the water to test, or did not clean the fractometer between use. Carefully recheck the reading and let us know what the reading were in ppt, not SG.
Minh Nguyen

 

[wombat1]

In talking with the manufacturer,he said to calibrate my unit in accordance to my source water,

8O 8O It's scary the MANUFACTURER told you this! He should know better... Minh's post is right on. IMO, it doesn't make much difference whether your SG is at 1.025 or 1.026, but if you're going to spend the money for a refractometer you might as well use it right.

 

[Robin Goodfellow]

It's scary the MANUFACTURER told you this!

hi.
Not really. Most of the manufacturer's main customers are using the refractometer for things like grape juice and antifreeze.

 

[Riotfishdude]

Thanks guys,always thought distilled was boiled water,i see i'm wrong again....well being wrong twice in my life isn't bad.. 8)

what the manu. told me didnt include tap water though,just so i'm not making him look like the bad guy.....

"To calibrate, please test your water source for your tank. Reverse Osmosis, Deionized or
Distilled. This is the "baseline" of starting point; adjust the unit to "0" here. From here on
out your unit will be calibrated against the virgin water before you chemically treat it (or
replenish).".......

ive got it all figured out now,thanks again.....Riot....

 

[attempt]

was looking around at refractometers and found this
http://www.premiumaquatics.com/thestore ... FRACT.html
The Acquamarine Refractometer is an incredibly accurate and easy to device that eliminates the confusion associated with inexpensive hydrometers. Just place a couple of drops of water on the prism and hold to the light. Reads in percent and specific gravity. An absolute must for the serious marine hobbyist.

The Acquamarine Refractometer is an optical device (no batteries) dual scaled 0-100% specific gravity: 1.0 to 1.070. Calibrate with distilled water. Adjustable eyepiece, carrying case, pipette and calibration screw driver included. *this model is ATC (auto temp compensating)*

 

[Riotfishdude]

yup,same instructions on mine,bought it from "National Industrial Supply" in Cali....$41US,pretty heavy duty units for the price,good guy i dealt with to....chardowner@yahoo.com
"NIS_Sales" on Ebay....Riot....