Hey Randy, curious about your take on the BRS videos with chaeto and nutrients. I remember your article below. However in brs video they found nutrient reduction but in drastically varying final harvest weights. It looks like the smaller mass has more color, do you think the total dry weights would tell a larger story? It almost seems like the chaeto can vary it's water weight - so the minimal weight gain could have been quite a bit more than the starting and ending weight if the chaeto lost overall % water weight and gained additional mass.
Thoughts?
http://www.bulkreefsupply.com/video...-best-refugium-light-and-what-is-coming-next/
Macroalgae are typically about 5% nitrogen and 0.1% phosphorus by weight (based on dry weight). So as it grows it removes a lot of nitrogen and phosphorus.
I discuss it here:
http://reefkeeping.com/issues/2006-09/rhf/index.php#12
from it:
Phosphate Export by Organisms: Macroalgae
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Growing and harvesting macroalgae can be a very effective way to reduce phosphate levels (along with other nutrients) in reef aquaria. In my reef system, where I have large, lit refugia to grow the macroalgae Caulerpa racemosa and Chaetomorpha sp., these algae are clearly the largest phosphate export mechanisms. Aquaria with large amounts of thriving macroalgae can avoid microalgae problems or excessive phosphate levels that might inhibit coral calcification. Whether the reduction in phosphate is the cause of the microalgae reduction is not obvious; other nutrients can also become limiting. But to reef aquarists with a severe microalgae problem, the exact mechanism may make no difference. If rapidly growing macroalgae absorb enough phosphorus to keep the orthophosphate concentrations in the water column acceptably low, and at the same time keep microalgae under control, most reefkeepers will be satisfied.
For those interested in knowing how much phosphorus is being exported by macroalgae, this free PDF article in the journal Marine Biology has some important information. It gives the phosphorus and nitrogen content for nine different species of macroalgae, including many that reefkeepers typically maintain. For example, Caulerpa racemosa collected off Hawaii contains about 0.08 % phosphorus by dry weight and 5.6% nitrogen. Harvesting 10 grams (dry weight) of this macroalgae from an aquarium would be the equivalent of removing 24 mg of phosphate from the water column. That amount is the equivalent of reducing the phosphate concentration from 0.2 ppm to 0.1 ppm in a 67-gallon aquarium. All of the other species tested gave similar results (plus or minus a factor of two). Interestingly, using the same paper's nitrogen data, this would also be equivalent to reducing the nitrate content by 2.5 grams, or 10 ppm in that same 67-gallon aquarium.
Thoughts?
http://www.bulkreefsupply.com/video...-best-refugium-light-and-what-is-coming-next/
Macroalgae are typically about 5% nitrogen and 0.1% phosphorus by weight (based on dry weight). So as it grows it removes a lot of nitrogen and phosphorus.
I discuss it here:
http://reefkeeping.com/issues/2006-09/rhf/index.php#12
from it:
Phosphate Export by Organisms: Macroalgae
--------------------------------------------------------------------------------
Growing and harvesting macroalgae can be a very effective way to reduce phosphate levels (along with other nutrients) in reef aquaria. In my reef system, where I have large, lit refugia to grow the macroalgae Caulerpa racemosa and Chaetomorpha sp., these algae are clearly the largest phosphate export mechanisms. Aquaria with large amounts of thriving macroalgae can avoid microalgae problems or excessive phosphate levels that might inhibit coral calcification. Whether the reduction in phosphate is the cause of the microalgae reduction is not obvious; other nutrients can also become limiting. But to reef aquarists with a severe microalgae problem, the exact mechanism may make no difference. If rapidly growing macroalgae absorb enough phosphorus to keep the orthophosphate concentrations in the water column acceptably low, and at the same time keep microalgae under control, most reefkeepers will be satisfied.
For those interested in knowing how much phosphorus is being exported by macroalgae, this free PDF article in the journal Marine Biology has some important information. It gives the phosphorus and nitrogen content for nine different species of macroalgae, including many that reefkeepers typically maintain. For example, Caulerpa racemosa collected off Hawaii contains about 0.08 % phosphorus by dry weight and 5.6% nitrogen. Harvesting 10 grams (dry weight) of this macroalgae from an aquarium would be the equivalent of removing 24 mg of phosphate from the water column. That amount is the equivalent of reducing the phosphate concentration from 0.2 ppm to 0.1 ppm in a 67-gallon aquarium. All of the other species tested gave similar results (plus or minus a factor of two). Interestingly, using the same paper's nitrogen data, this would also be equivalent to reducing the nitrate content by 2.5 grams, or 10 ppm in that same 67-gallon aquarium.
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