I am trying to lower my nitrates in my 46 gallon tank and wanted to get macroalgea to help - I know culerpa (many different forms) help but it spreads aggressively right? Is there one that does not spread as aggressively, i.e. Red Mangrove propagule? Or does that also spread aggresively? If I get culerpa how often do I prune it so it doesn't spread as aggresively?