sghera64
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Things you can do with ultra low sensitivity (Parts Per Billion)
My initial reading was 2 ppb (P). I know there is more than that in my system. I know the checker can only quantify inorganic phosphorous in the water column. It cannot detect phosphorus (or phosphate) that is sequestered in the coral or plant (hair algae) tissue. So, I did two experiments.
Experiment 1: The sample that scored 2 ppb-Phosphorous, I set aside for 2 days in the dark. I wanted to provide time for any water borne plant cells or organically bound phosphorous to have a chance to decompose and set the P free. After two days, the checker gave me 0 ppb (P). My take on that is I did not give it enough time and the “living†stuff in the water actually gobbled what little was left there. Or, my levels of free Pi did not change and 0 is within the repeatability of the checker.
Experiment 2: I did a “lights out for 3 day†to reduce hair algae. On day 2 and 3, I checked the phosphate (phosphorous) levels of the display tank (DT). On day 2, it was 10 ppb-P (remember it was 2 before the experiment). On day 3, it was 36 and 44 ppb-P. I checked it 2 times within 2 hours of each other. That 44 ppb-P is the same as 135 ppb-PO4 or 0.135 ppm-PO4. This seems to me that the lights out period does what I was told it would do: free’s up some of the phosphorous that is freed up in the living tissue of algae (and hopefully not too much of what is in my coral).
I am running ROWAphos. Part of the reason I did experiment 2 is to check the theory that lights out can free sequestered P. The other reason is to see if the ROWAphos can adsorb this faster than it was given up. I know as soon as I turn on the lights, it will be a race back to 2 ppb-P between the ROWAphos and the algae that is in the tank.
As a side note, I did run another experiment with the checker. Mine turns off sometimes if I take too long to dissolve the reagent in the water sample. Instead of trashing my water sample and starting over, I kept the sample with reagent in it. I pulled out the second cuvette, rinsed it a few times with DT water and made it a “blankâ€. I restarted the checker, “zeroed†it with the 2nd cuvette of water as the blank and then took my reading with the original reacted water sample. It “seemed†to work and give a valid reading. I verified this by rinsing out both cuvettes, filling both with tank water. I did not react either one this time. Instead, I used one to zero the checker (steps C1 to C2), and then did a reading on the second cuvette (unreacted). I expected to get a zero reading. After three minutes - - I got zero ppb-P. I then repeated this experiment but switched positions of the cuvettes. Again, I got zero. This means that the checker did not see a positive increase in P between the water in the two cuvettes and between the two cuvettes themselves. A positive difference would have meant that either the water was different in the two or the glass (or its surface was different - - e.g. finger prints, scratches, thickness, bubbles, etc.). My conclusion is that I can use one cuvette to be the blank and the other for the reacted water sample and I don’t have to worry about sample error due to using two different cuvettes. This saves time and reduces the risk of the checker timing out between C2 and the 3 minutes assay part.
Another think I do is to cut the top of the packet off and carefully separate, by hand, the seams on the left side and right side of the packet. This exposes all the reagent in the packet. I do this “separation†in a way such that I don’t spill any over the open seams. With all the powder resting on one side of the sachet or along the (still sealed) bottom seam, I form a “V†crease down the middle of the side that contains the power. When it is time to add this to the water sample, I simply place the bottom of the “V†into the mouth of the cuvette and gently tap until all the powder goes in. With the sachet completely open, I can see that I transferred all the reagent.
My initial reading was 2 ppb (P). I know there is more than that in my system. I know the checker can only quantify inorganic phosphorous in the water column. It cannot detect phosphorus (or phosphate) that is sequestered in the coral or plant (hair algae) tissue. So, I did two experiments.
Experiment 1: The sample that scored 2 ppb-Phosphorous, I set aside for 2 days in the dark. I wanted to provide time for any water borne plant cells or organically bound phosphorous to have a chance to decompose and set the P free. After two days, the checker gave me 0 ppb (P). My take on that is I did not give it enough time and the “living†stuff in the water actually gobbled what little was left there. Or, my levels of free Pi did not change and 0 is within the repeatability of the checker.
Experiment 2: I did a “lights out for 3 day†to reduce hair algae. On day 2 and 3, I checked the phosphate (phosphorous) levels of the display tank (DT). On day 2, it was 10 ppb-P (remember it was 2 before the experiment). On day 3, it was 36 and 44 ppb-P. I checked it 2 times within 2 hours of each other. That 44 ppb-P is the same as 135 ppb-PO4 or 0.135 ppm-PO4. This seems to me that the lights out period does what I was told it would do: free’s up some of the phosphorous that is freed up in the living tissue of algae (and hopefully not too much of what is in my coral).
I am running ROWAphos. Part of the reason I did experiment 2 is to check the theory that lights out can free sequestered P. The other reason is to see if the ROWAphos can adsorb this faster than it was given up. I know as soon as I turn on the lights, it will be a race back to 2 ppb-P between the ROWAphos and the algae that is in the tank.
As a side note, I did run another experiment with the checker. Mine turns off sometimes if I take too long to dissolve the reagent in the water sample. Instead of trashing my water sample and starting over, I kept the sample with reagent in it. I pulled out the second cuvette, rinsed it a few times with DT water and made it a “blankâ€. I restarted the checker, “zeroed†it with the 2nd cuvette of water as the blank and then took my reading with the original reacted water sample. It “seemed†to work and give a valid reading. I verified this by rinsing out both cuvettes, filling both with tank water. I did not react either one this time. Instead, I used one to zero the checker (steps C1 to C2), and then did a reading on the second cuvette (unreacted). I expected to get a zero reading. After three minutes - - I got zero ppb-P. I then repeated this experiment but switched positions of the cuvettes. Again, I got zero. This means that the checker did not see a positive increase in P between the water in the two cuvettes and between the two cuvettes themselves. A positive difference would have meant that either the water was different in the two or the glass (or its surface was different - - e.g. finger prints, scratches, thickness, bubbles, etc.). My conclusion is that I can use one cuvette to be the blank and the other for the reacted water sample and I don’t have to worry about sample error due to using two different cuvettes. This saves time and reduces the risk of the checker timing out between C2 and the 3 minutes assay part.
Another think I do is to cut the top of the packet off and carefully separate, by hand, the seams on the left side and right side of the packet. This exposes all the reagent in the packet. I do this “separation†in a way such that I don’t spill any over the open seams. With all the powder resting on one side of the sachet or along the (still sealed) bottom seam, I form a “V†crease down the middle of the side that contains the power. When it is time to add this to the water sample, I simply place the bottom of the “V†into the mouth of the cuvette and gently tap until all the powder goes in. With the sachet completely open, I can see that I transferred all the reagent.
