How to grow duckweed [Archive] - Canadian Aquarium Connection - Canada's Fish Community

OldMan

Apr 18th 2010, 07:59 AM

I gave it a read through and was a bit surprised to find that the concentrations of ammonia that worked well for growth were well outside any value we might find in an aquarium. It seems that only having the nitrogen present as nitrates would work at all in an aquarium setting. Otherwise all the dead fish would affect the growth outcome. The values they tested were from 92 ppm to 9 ppm, a bit high for ammonia in my tanks. At the lowest tested value, they found the ammonia form outproducing the nitrate form but our fish can often tolerate the much higher levels of nitrate where the nitrate dominated the fast growth of duckweed. It looks like duckweed prefers the water chemistry that our fish do, where nitrates are a much better food in high concentrations than ammonia.