Atari Posted January 9, 2009 Author Share Posted January 9, 2009 I don't have a refractometer but I would image calibrating it with RO/DI water would be like calibrating your speedometer while in park. My hydrometer reads 0 when I fill it up with RO/DI water does that mean it’s properly calibrated? Link to comment
StevieT Posted January 9, 2009 Share Posted January 9, 2009 I don't have a refractometer but I would image calibrating it with RO/DI water would be like calibrating your speedometer while in park. My hydrometer reads 0 when I fill it up with RO/DI water does that mean it's properly calibrated? Good comparrison. You don't calibrate anything mechanically to its zero level, scales, your car, air pressure, fuel level, etc. I too thought RO/DI was fine, after receiving the solution I found my refractor was off by a few ppt and that can make a huge difference in your reef. Link to comment
Sac_State Posted January 9, 2009 Share Posted January 9, 2009 Honestly I use a refractometer because they're so quick. I just dip the end in my tank and pull it out, point it at a light, and presto. plus its so easy to clean. It's worth the money I think. You're dipping the whole end of your refractometer into your tank?? That's crazy talk! Link to comment
Phixion Posted January 9, 2009 Share Posted January 9, 2009 Ro/di should not have any salt at all, 0 ppt. That is the point of reference. If you put the drops of ro/di water in the refractometer and adjust the screw to level the shaded area at zero, then that would be the base reading - zero. The solution is helpful because it gives you a point of reference but there is more than one way to get to the same point of reference. If a calibration solution says it is at 1.019 you adjust the screw in the refractometer until it reads 1.019. If you have no salt in the water, then the reading should be at zero, if not adjust the screw to show the reading at zero. Another example would be a weight scale. You have to calibrate it to zero by turning a nob, etc, before you actually measure weight. The reason NOT to calibrate with RO/DI is that sure you can match it to 1.000 S.G. or 0 ppt, but once you put some 35ppt solution on the lense, it won't read at 35ppt like it's supposed to. This is because many cheaper refractos have a curved lense and not straight like it should be. So you calibrate to 35ppt as that's what ocean water should be at slinity wise, so thus you're more accurate for the water you're testing. Now for me as I've mentioned, I'm fortunate enough to have a refrato (given it is a cheaper one) that WILL calibrate properly at 0 with RO/DI and then read 30ppt solution correctly at 30ppt... Oddly, when I calibrate my refracto to 30ppt and then my Aqua-Mate digital salinity meter also to 30ppt, they read my tank water at different S.G. and ppt amounts. I can't figure this one out for the life of me... Both will read out RO/DI at 0 when calibrated to 30ppt. Not sure why the deviation exists though. Link to comment
davidncbrown Posted January 9, 2009 Share Posted January 9, 2009 You're dipping the whole end of your refractometer into your tank?? That's crazy talk! Well just up to the glass window, not as far up as the calibration screw. When the plastic cover falls down on top of it then I take it out. When I'm done I rinse it under tap water, dry it off and put it back in its home. Oh and I have a baggy of desiccant in the case to absorb any water I missed while drying off. Link to comment
Scott Riemer Posted January 9, 2009 Share Posted January 9, 2009 Well just up to the glass window, not as far up as the calibration screw. When the plastic cover falls down on top of it then I take it out. When I'm done I rinse it under tap water, dry it off and put it back in its home. Oh and I have a baggy of desiccant in the case to absorb any water I missed while drying off. Why not drop a few drops on the prism with a pipette? Link to comment
Atari Posted January 9, 2009 Author Share Posted January 9, 2009 Well just up to the glass window, not as far up as the calibration screw. When the plastic cover falls down on top of it then I take it out. When I'm done I rinse it under tap water, dry it off and put it back in its home. Oh and I have a baggy of desiccant in the case to absorb any water I missed while drying off. WOW! Sounds like a refractometers takes more work to properly maintain the a hydrometers Link to comment
supreme_spork Posted January 9, 2009 Share Posted January 9, 2009 Why not drop a few drops on the prism with a pipette? ^this. WOW! Sounds like a refractometers takes more work to properly maintain the a hydrometers Not at all... you just need to rinse it off and dry it when you're done. Link to comment
StevieT Posted January 9, 2009 Share Posted January 9, 2009 WOW! Sounds like a refractometers takes more work to properly maintain the a hydrometers no. only if you dunk it in the tank. If you use a few drops on the glass, all you need to to is whipe it off when you are done. If it is still wet salt won't build up. I clean mine every now and then with fresh water, just the part that gets salt water on it. Link to comment
davidncbrown Posted January 9, 2009 Share Posted January 9, 2009 Why not drop a few drops on the prism with a pipette? Because if you don't rinse the pipette every time with fresh water salt can build up inside the tube and even a little salt build up makes a difference in a small sample (couple drops) of water. I find it just easier because its one less thing to clean. I calibrate my refractometer once a month with a 35ppt solution. Link to comment
supreme_spork Posted January 9, 2009 Share Posted January 9, 2009 Because if you don't rinse the pipette every time with fresh water salt can build up inside the tube and even a little salt build up makes a difference in a small sample (couple drops) of water. I find it just easier because its one less thing to clean. I calibrate my refractometer once a month with a 35ppt solution. It takes less than 5 seconds to rinse a pipette! When it comes to dunking my delicate scientific instruments in salt water vs. spending 2.748 seconds to rinse a pipette, the right answer is clear... Link to comment
davidncbrown Posted January 9, 2009 Share Posted January 9, 2009 It takes less than 5 seconds to rinse a pipette! When it comes to dunking my delicate scientific instruments in salt water vs. spending 2.748 seconds to rinse a pipette, the right answer is clear... I guess you guys don't understand what I'm doing... I'm not dunking the refractometer in the water, I'm placing almost the entire prism into the water and letting the plastic cover fall down on top of it which covers the entire prism with water. I would never dunk the whole thing or even half of it in the water because I don't want water getting inside. The first place water could get inside is where the set screw is for calibration and I would never place it that far under water. I've done this for almost a year with my refractometer and never had any problems. I'm not condoning it, you are obviously free to do what you wish, but this is how I test my tank and it works for me. Link to comment
Sac_State Posted January 9, 2009 Share Posted January 9, 2009 Because if you don't rinse the pipette every time with fresh water salt can build up inside the tube and even a little salt build up makes a difference in a small sample (couple drops) of water. I find it just easier because its one less thing to clean. I calibrate my refractometer once a month with a 35ppt solution. seems to me like it would be alot easier to rinse out the pipette than it would be to clean the whole end of the refractometer...but that's just me. and yes, we get what you're saying; it just seems...unnecessary. Link to comment
davidncbrown Posted January 9, 2009 Share Posted January 9, 2009 seems to me like it would be alot easier to rinse out the pipette than it would be to clean the whole end of the refractometer...but that's just me. I dunno I just run the end under water for a few seconds and wipe it off with a paper towel. For me its one less thing to deal with (the pipette). I do the same thing with my brix refractometer when I brew beer. Link to comment
el fabuloso Posted January 9, 2009 Share Posted January 9, 2009 I voted refractometer because it's quick, accurate and easy to use especially in a small tank. Hydrometers are a PITA to use in picos. Link to comment
Atari Posted January 9, 2009 Author Share Posted January 9, 2009 I voted refractometer because it's quick, accurate and easy to use especially in a small tank. Hydrometers are a PITA to use in picos. I can see that. There are a lot more votes for hydrometers then I was expecting. : Link to comment
StevieT Posted January 9, 2009 Share Posted January 9, 2009 I can see that. There are a lot more votes for hydrometers then I was expecting. : cheap bastards Link to comment
psykobowler Posted January 9, 2009 Share Posted January 9, 2009 Right RO has nothing in it, so our refractor would be calibrated to a zero level. But, you are not testing your tank to find a zero level, it is not like a scale where you tare it. You are trying to find a salt level and most $40 refractors need a slight adjustment to find this accurately. Just like a scale, when you have a professional service come out to callibrate it, they do not just tare it out, they measure it with materials that have known weights. So you callibrate with a solution that has 35ppt, set your refractor to that known value and now your prisim is in the correct postition. You can experiment with this if you want to see how off it can be. Try RO/DI water first. Then the calibration solution at 77°. I absolutely agree that a solution would yield accurate results because you are paying for that point of reference. And if given an option I would choose the solution over ro/di water but I am arguing against it as the only option and an absolute necessity. I am saying spend the money on a good refractometer that will calibrate at 0ppt. You can get an atc which has instruction to use distilled water, set it at 0 and be done with it. If it is really off then you paid for a bad merchandise but overall you cannot exaggerate the difference. I am glad specific gravity is recommended within a specific range for marine life and not exact science. As long as you have a tool that will get you there closer then you are good. I am just not in favor of swing arm hydrometer where the measurement will be influenced by its mechanical part. Going back to the weight thing- I am not arguing exact measurement just enough to get good results. There are usually more than one solution to every problem. Link to comment
Phixion Posted January 9, 2009 Share Posted January 9, 2009 ^^^ Still missing the point I think. Anyways, that's why I use my digital meter instead of refract. Cleaning it can't be faster, even the dunk, view and rinse as been described is slower than how fast my digital works. </bragging> I should vote hydro just to p1ss more people off, lol! Link to comment
Scott Riemer Posted January 9, 2009 Share Posted January 9, 2009 It's $3 for calibration solution. I'll pay $3 for piece of mind about my salinity in my tank with $1,000+ invested. Link to comment
Atari Posted January 9, 2009 Author Share Posted January 9, 2009 It's $3 for calibration solution. I'll pay $3 for piece of mind about my salinity in my tank with $1,000+ invested. I think if your willing to front the Bling to get the refractometer then you better be willing to pay for the upkeep cost. Link to comment
StevieT Posted January 9, 2009 Share Posted January 9, 2009 I think if your willing to front the Bling to get the refractometer then you better be willing to pay for the upkeep cost. Which there is none. That bottle will last you forever. You only use a few drops to callibrate it, then it should be set. I have checked mine a few other times since (15 months old) and it has always been pretty spot on. I don't know if it goes bad or evaporates causing an issue, it is in a sealed bottle. Link to comment
Phixion Posted January 9, 2009 Share Posted January 9, 2009 Which there is none. That bottle will last you forever. You only use a few drops to callibrate it, then it should be set. I have checked mine a few other times since (15 months old) and it has always been pretty spot on. I don't know if it goes bad or evaporates causing an issue, it is in a sealed bottle. That would be my only concern. But they never say it needs to be replaced... Link to comment
Sac_State Posted January 9, 2009 Share Posted January 9, 2009 Anyways, that's why I use my digital meter instead of refract. Cleaning it can't be faster, even the dunk, view and rinse as been described is slower than how fast my digital works. </bragging> unless that digital salinity meter is one of the higher lab grade types, such as a Pin Point or American Marine unit, then I wouldn't trust that either...and if you're talking about one of those JBJ handheld units, forget about it, that thing is about as reliable as a swing arm. digital units need to be calibrated just as often, if more more, than refractometers. The great thing refractometers is the very fact that they are not electronic, and are therefore not subject to electronic error and miscalculation. Link to comment
StevieT Posted January 9, 2009 Share Posted January 9, 2009 That would be my only concern. But they never say it needs to be replaced... I have always questioned this. Bassically what is the calibration solution made of? Is the sealed top air tight? How old is the bottle after it is shipped to start with? There is never much instruction with these solutions, but my bottle still seems fine after 15-16 months so I don't worry too much. I still would like to find out though. Link to comment
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