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#1
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phosphorus standard
Anyone know where I can get a low range phosphorus standard? I want to check the accuracy of my photometer.
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#2
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I've had to make them myself, but perhaps others have some ideas. It would be especially useful for it to be in seawater, otherwise it is not an especially good test.
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Randy Holmes-Farley |
#3
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Wow, I see a new line of future reef products. Randys Standards.
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#4
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It would be nice for someone to sell such products.
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Randy Holmes-Farley |
#5
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I tested for PO4 yesterday and got a reading of 0.05. I changed the GFO four days before that. Today I tested and I got a reading of 0.0. I suppose this is possible, but I wonder how accurate that reading is. (I did it 3 times) .
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#6
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I do not know how accurate it is either, but enough GFO can pull the phosphate down fairly quickly.
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Randy Holmes-Farley |
#7
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I would think you would be able to find a standard through an industrial supply co.
Is this is the low-range Hanna photometer? If I remember correctly, the manufacture claims it is accurate to .04mg/L or 15% of the reading - whichever is larger. So your PO4 should have gone down by at least .01mg/L
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Some people say, "How can you live without knowing?" I do not know what they mean. I always live without knowing. That is easy. How you get to know is what I want to know. - Richard Feynman |
#8
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It is easy enough to get standards, just not in seawater. Here's one from Cole Parmer (they have many):
http://www.coleparmer.com/catalog/pr...sp?sku=8697450
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Randy Holmes-Farley |
#9
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I have the milwaukee photometer. Since you zero the instrument with the liquid your going to test before you add reagent, why is it important to have a seawater standard? Is it the reagent?
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#10
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Other ingredients in seawater may react with the reagents, or prevent the reaction of phosphate with the reagents in ways that alter the result, either upward or downward.
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Randy Holmes-Farley |
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