Water Quality is critical in a marine aquarium.   I have been fortunate to achieve a balanced system where the temperature, salinity and Ph stay constant, ammonia and nitrites are virtually undetectable, and nitrates are kept under control with frequent water changes.  I do, however, have a problem with Algae Blooms.  I have been using tap water that sits for a minimum of 3 days before it is used, but here in Northeast Ohio, our water is famous for having phosphates in the water.  Phosphates encourage algae growth, and I have been told that phosphate removers on the market simply do not work.  I do own a Culligan Reverse Osmosis (RO) unit, but seeing as we will be moving soon, I didn't want to install it, just to uninstall it in a few months.   OK, OK... I'm lazy!