finally got my pinpoint 53.0ms solution. When using ro/di water and set to 0, my tank water was reading 1.025-1.026.
after reading the RC article and several other sources i calibrated my refract using the 53.0ms solution and it read 40ppt. I reset the meter to this measurement and retested using ro.do water, my tank water and finally the pinpoint solution again.
I feel that this is a rather significant error as my tank water now only reads at 1.022 and RO/DI is far below the 1.000 mark.
my unit is one of the ebay salinity units with ATC. it has scales for specific gravity and ppt.
I suppose what I am asking is if this much of an error is a concern once properly calibrated? This is assuming ofcourse that the pinpoint solution i bought from the store is indeed 35ppt.
this may explain though why I have been battling GHA the last year despite using a salt that is high in magnesium and having no fish in the tank.
QUOTE (sayn3ver @ Nov 8 2009, 12:15 PM) 
finally got my pinpoint 53.0ms solution. When using ro/di water and set to 0, my tank water was reading 1.025-1.026.
after reading the RC article and several other sources i calibrated my refract using the 53.0ms solution and it read 40ppt. I reset the meter to this measurement and retested using ro.do water, my tank water and finally the pinpoint solution again.
I feel that this is a rather significant error as my tank water now only reads at 1.022 and RO/DI is far below the 1.000 mark.
my unit is one of the ebay salinity units with ATC. it has scales for specific gravity and ppt.
I suppose what I am asking is if this much of an error is a concern once properly calibrated? This is assuming ofcourse that the pinpoint solution i bought from the store is indeed 35ppt.
this may explain though why I have been battling GHA the last year despite using a salt that is high in magnesium and having no fish in the tank.
after reading the RC article and several other sources i calibrated my refract using the 53.0ms solution and it read 40ppt. I reset the meter to this measurement and retested using ro.do water, my tank water and finally the pinpoint solution again.
I feel that this is a rather significant error as my tank water now only reads at 1.022 and RO/DI is far below the 1.000 mark.
my unit is one of the ebay salinity units with ATC. it has scales for specific gravity and ppt.
I suppose what I am asking is if this much of an error is a concern once properly calibrated? This is assuming ofcourse that the pinpoint solution i bought from the store is indeed 35ppt.
this may explain though why I have been battling GHA the last year despite using a salt that is high in magnesium and having no fish in the tank.
Clarify, your 2nd paragraph states your instrument read 40ppt with the salinity calibration solution, and you set it that way? I'm not positive I understand what you mean. You should adjust the instrument to read 35ppt with the calibration solution. And from what I've read, refractometers often read slightly high when calibrated with RO/DI or distilled water, but using the 35ppt/53.0ms solution (our tanks range is at this point) they read correctly.
I don't think it ought to matter if its an ebay instrument or not, once you calibrate it against a known substance, it should be accurate.
I bought one off ebay too...I think it was around $25 or so? It SEEMED to be okay, but kinda hard to read because the lines were very small.
My candy canes hadn't been opening up much, and I think my evaporation looked high, (meaning I was adding a LOT of top off water, and in the back of my mind wondering about too much dilution?) so I finally just stopped adding top off for a day, then checked it with my swing arm, and it was 1.023 AFTER a full days evaporation! I dont' even want to know what salinity my poor corals were at for about a week
Hopefully no long term damage done, After several days and adding 1.025 water as a top off, I got it back up to the 1.026 I want it at. I recommend tossing the crappy cheap refracts, sticking with a reliable EVEN if its a swing arm, and cross checking with other ones as well.
My candy canes hadn't been opening up much, and I think my evaporation looked high, (meaning I was adding a LOT of top off water, and in the back of my mind wondering about too much dilution?) so I finally just stopped adding top off for a day, then checked it with my swing arm, and it was 1.023 AFTER a full days evaporation! I dont' even want to know what salinity my poor corals were at for about a week
Hopefully no long term damage done, After several days and adding 1.025 water as a top off, I got it back up to the 1.026 I want it at. I recommend tossing the crappy cheap refracts, sticking with a reliable EVEN if its a swing arm, and cross checking with other ones as well.
correct, uncorrected the meter read 40ppt so i calibrated it down to the 35ppt that the 53.0ms is supposed to be. however, it makes me wonder is the accuracy just off or is the instruments precision off as well?
I would be suspect. If it reads way below 1.00 with RO/DI when adjusted to 35ppt with your solution then one of the 3 is off. If your tank has been doing well as you have been mixing your salt I would not use the refractometer until you discover which one is in error.
Mark
For a buck you can go get a gallon of distilled water that the grocery store and eliminate the possibility that your RO/DI is the problem. Distilled is great for top offs, so it wont go to waste
Mark
For a buck you can go get a gallon of distilled water that the grocery store and eliminate the possibility that your RO/DI is the problem. Distilled is great for top offs, so it wont go to waste
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