It depends on what you plan on keeping in your tank as to wether your filter is good enough. For fish only systems, you probably have the bare minimum of what will work. For reef systems, you need to upgrade. What kind of skimmer do you have?
I noticed that your filter is rated at 500 gph max. This is not enough turnover for good filtration. I don't remember the exact specs, but many people use about a 15-20x turnover ratio for their tanks. So on a 55 gal tank, you want to have a filter that can handle 15-20x your tank volume per hour, or 825-1100 gph.
Also, do you have any powerheads? You want at least 1 or 2 to mix the water in your tank. These create currents within your tank that help to evenly distribute oxygen throughout your tank and also help at maintaining an even temperature. If you have sand substrate, you want them high in the tank and have the pointed down so that they lightly blow down onto the sand so that it doesn't get kicked up. If you have crushed coral, you want your powerheads low so that it can keep it free of debris.
Do you have any living rock? This really helps in filtration also. Get at least a pound per gallon.
If you used unfiltered water to fill your tank, then you need to empty it out and refill it with either RO,DI or distilled water. This should be the first thing you do because until you remove the source of your polution, your filter will never clean it enough to clear up the algae. Do a water change with good water and always be sure to top off your tank with filtered water also.
It may be good to add some carbon to your tank after you do your water change so that it will absorb any excess waste that was put in by the bad water. Be sure to rinse it out completely before you put it in your tank or it will cloud your tank. Also you might want to add a phosphate remover. These will both be temporary. They are only there to clean out the remainder of the pollutants that the water change did not fix. Leave the carbon and the phosphate remover in there for about a month and then throw it away.
Also, take a soft brush (like a tooth brush) and clean off all your rocks, etc. to remove all the algae you can. Then clean off your glass. Do this before you do your water change so that you will remove the algae with the water change.