Refractometer

[11f150]

Im in need of one and came across this one, what do you think? Seems like a low price.

Salinity Salt Refractometer 4 Aquarium, Hydrometer SOFTCASE - APRIL BLOWOUT!

 

[Dowtish]

looks just like mine. so order some calibration fluid for it from BRS

 

[Bishop]

same one I have always used. I calibrate mine with tap water but there is certainly no reason not to get calibration fluid... Insures a better accuracy.

 

[sluicebox]

same one I have always used. I calibrate mine with tap water but there is certainly no reason not to get calibration fluid... Insures a better accuracy.

How in the heck do you calibrate with tap water? I've heard of using RO/DI for a zero calibration but I don't think you have a clue of what's coming from the tap!

 

[VandyTime]

i use distilled water

 

[sluicebox]

i use distilled water

Then you have a zero calibration which is a start. But, for accuracy, I think you should have a span calibration as well. Something near the range of interest for your salt water. Thus, the calibration fluid which is 1.025 specific gravity equating to 35.5 salinity @ 25 degrees C. I think you'll find that a span calibration will yield different results then what you've been getting with a zero calibration only.

 

[Dowtish]

I think we have covered this before. But its worth repeating. If you use a refractometer to measure around 1.025 to 26, which is on the higher end, why would you want to calibrate it at zero? Which is the lowest end. If you search the forums you will find all kinds of threads where people were having issues and couldnt figure out why their corals were not doing well. Then after exausting all efforts, they try calibration fluid and find out their refractometer was off by 4-5 points! because they had always just calibrated to zero wih rodi.

 

[EvilMel]

Over in ETRC most of us calibrate with a solution that's 35 parts per thousand NaCl. It's a solution that I make in the lab and just pass out to anyone who wants some. It doesn't make any sense to calibrate your refractometer with a solution that's mega-far away from the range you'll be using it (e.g. calibrating with tap water). You should always calibrate it with a solution that's close to the range in which you will use the instrument.

 

[Dowtish]

Over in ETRC most of us calibrate with a solution that's 35 parts per thousand NaCl. It's a solution that I make in the lab and just pass out to anyone who wants some. It doesn't make any sense to calibrate your refractometer with a solution that's mega-far away from the range you'll be using it (e.g. calibrating with tap water). You should always calibrate it with a solution that's close to the range in which you will use the instrument.

Exactly

 

[EvilMel]

What he said!

 

[gmoney243]

Yes recently helped out a reefer whos salinity kept moving around because he was calibrating with distilled water and his would move around between .026-.027 which was odd. So we calibrated using my liquid plus my refractometer and turns out his salinity was really .022 his corals are much better now.

Sent from my VS930 4G using Tapatalk 2

 

[VandyTime]

Got some calibration fluid in yesterday and tested and sure enough, been running my salt way to low!

 

[SmyrnaReefer]

same here got mine saturday (yesterday) some how my tank is still alive... i was calibrating with RO water. not any more

 

[kemper6120]

Yes recently helped out a reefer whos salinity kept moving around because he was calibrating with distilled water and his would move around between .026-.027 which was odd. So we calibrated using my liquid plus my refractometer and turns out his salinity was really .022 his corals are much better now.

Sent from my VS930 4G using Tapatalk 2

And everything is alll soo happy! :wink:

 

[quigimon]

Best analogy to calibrating with a zero calibration liquid is like trying to shoot from the hip with a rifle at a quarter mile away, where calibrating is like using a scope to do the same job.

 

[EvilMel]

i was calibrating with RO water. not any more

Seriously? Of all people! I'm shocked.