Help with some choices on sumps, filtration etc

I began my tank with a 29 gallon salt water. Before I invested too much time and money, I wanted to see if I could manage an aquarium so I started out small. I needed to grasp the concept on my own of the set up, with all the equipment, clean-up etc. I have maintained perfect water perimeters for a year, religiously change 15%-20% water changes every Tuesday with RO Primo water from Walmart.Everything is going great, all my little guys are healthy and happy. The problem is the foul, horrid, ugly ALGAE monster has never left my tank. Fortunately my fish are not suffering at all. I’m looking to upgrade to a 80 gallon, and hopefully some of the algae problem will be solved and the tank will be easier to maintain. So, this is where I am completely blank. With a small tank I only used a fluval hang on filter with a protein skimmer. I have the lighting, the heaters, rock, substrate figured out over the year. What type of filtration system would you suggest for the beginner of an 80 gallon tank? I don't have much room and sometimes I see these massive filters on youtube that are bigger than the tank itself.