|07-01-2015 02:27 PM|
You can skip GH and buy a cheap digital TDS meter ($10). TDS is a good way to test water softness/hardness.
You can make a simple NaCl (table salt) calibration solution. 1mg/L is 1ppm. And there's about 5690 mg in a teaspoon. A meter only goes up to 1000ppm so you'll have to dilute the solution.
|07-01-2015 02:01 PM|
|07-01-2015 05:15 AM|
|Hoppy||My experience is that GH test kits have a very limited shelf life before they just stop changing color when you try to use them. There is no reason I'm aware of to measure GH with much accuracy, so even a poor test kit, that is off 20% on the readings, is adequate. For that reason I don't think it is worth the trouble to figure out a good easy way to calibrate a GH test kit, but I'm sure it can be done.|
|07-01-2015 01:22 AM|
|keymastr||Any way to calibrate a GH test? My API tests are impossible to read. The color gets just slightly darker green/green yellow with each drop but does not ever make the dramatic change that I have seen of other peoples tests. I guess it may have been a bad kit.|
|04-21-2015 07:02 PM|
|Malakian||Big misunderstanding from my part, been a lot of that lately. Thanks for clearing it up for a brick headed viking|
|04-21-2015 06:58 PM|
|Hoppy||You can't mix a known sample of nitrate in water, for example, then add the test reagent to get the color, then save that colored sample to refer back to later. The color comes from dyes in the reagents, and dyes are not stable chemicals. You might be able to store them for a week or so, but definitely not for years.|
|04-21-2015 06:26 PM|
yes, that was what I meant. So to ask in another way, can you make calibrated solution for all tests/brands and store them indefinitely? Or is it test/brand (chemicals used for the tests) dependent? As in some test/brand use organic chemicals?
Bump: nevermind, think I got it know. You mean you can store the, say 25ppm,50ppm NO3 made up solutions, then add new test reagent to both calibrated water and tank water, as in you have to first do the calibrated solution test every time to get a reference for the tank test? I thought you meant you could mix it up to show the color, then store it? Sorry, I am a bit confused now..
|04-21-2015 06:10 PM|
|04-21-2015 05:17 PM|
|04-21-2015 02:09 AM|
|Hoppy||If the test sample is made up of inorganic chemicals and water, you can store them indefinitely, as long as none of the water evaporates. That can be hard to do.|
|04-21-2015 12:25 AM|
test sample longevity
How long will the calibrated test samples stay true ? Do they need to be stored at a certain temp , or does it matter ?
|08-05-2014 10:00 AM|
|08-05-2014 01:01 AM|
The most accurate ones I have used are made by LaMotte, but they are pricy.
Of course, with any test kit, once calibrated, you can expect a reasonable degree of precision. With more expensive test kits, you will get both precision and accuracy.
|08-04-2014 11:13 AM|
|manlyfan76||What kit do ppl think is best for Nitrates? or should we use any kit with the help of the calibration?|
|05-14-2014 05:28 PM|
This thread has been linked to recently and there were requests for pH calibration.
This link gives a description of a high range calibration solution using 1/2 tsp of borax to a pint of water at a known temperature. Somewhere around room temperature should be sufficient enough for the accuracy of these kits. There is also a link in the article for lower pH solutions.
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