Quote:
Originally Posted by Subsea
When I grew Graciilaria Parvispora ( Red Ogo) commercially, I sent it off to a scientific lab to be analyzed. It is my belief that seaweed will absorb anythig in the water. I expected the 30:1 ratio of nitrogen to phosphorous but not the 5:1 ratio of potassium to nitrogen nor the 2:1 ratio of sulphur to nitrogen. I am rethinking my nutrient dosing procedures.
Gracilaria Parvispora dry weight analysis:
Nitrogen @ 2.50%
Phosphorous @ 0.082%
Potassium @ 13.54%
Calcium @ 0.555%
Magnesium @ 1.163
Sulfur @ 4.82
Zinc @ 139ppm
Iron @ 107ppm
Manganese @ 20ppm
Copper @ 7.0 ppm
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Potassium is an important and often overlooked macro nutrient for macrophytes. This is why most diy macro fertiliser mixes for planted freshwater tanks are based on KNO3 and K2PO4 and depending on your needs maybe some additional K and Mg as well.
I'm surprised given the amount of testing and dosing of things like Ca/Mg/Alk that when someone asks about bumping their nitrate up the stock answer is a rather imprecise feed more.
Adding inorganic nitrate via NO3 has the benefit of being exactly calculable to a specific ppm value and not being derived via the nitrogen cycle it has no impact on BOD (biological oxygen demand). I do appreciate adding more food has other benefits such as providing the corals and filter feeding animals with additional particulate matter but it all depends on your goals