I was wondering if one could use mangroves to reduce organics in freshwater tank. This won't be necessary for a high-lighted tank, but what about the low-tech setups. How effecient are these plants at sucking up nitrates(I heard they are better than protein skimmers in SW!), are they better than regular emersed plants? I'm interested in this method in an attempt to reduce water changes on my low-tech setup.