I've found weekly water changes with a good clean up crew plenty to prevent algae issues. I did have a hair algae problem around six months ago but was able to get it under control by manually cleaning the rocks and then introducing a number of turbo snails to keep it down (they are AMAZING <3). Furthermore, I must say that the hair algae problem came from boyfriend's tank who was running a skimmer, sump and the works. It was actually much worse in his tank then in mine. Having a smaller system allows you to do bigger water changes more frequently and easily which helps remove all the junk not just what a skimmer can pull out. That said doing big water changes does tick off coral and make your tank cloudy for a day which is kind of a bummer, plus I imagine it can result in some swings in parameters so probably not the best if you're planning to keep acros. I've personally had great success with this method in keeping mid-end(?) montis (sunset,starburst), mid-end zoas (gold mauls, lazor lemons, peachy blues, ect), acans (echinatas, lords), rock flower nems and euphillas (torch, frogspawn). I do weekly water changes of 20%(sometimes 40% if I have the spare water) or every other week 40% (if I'm particularly busy). Just to clarify this is not 20% of the tanks total volume but of what I guess the total volume of water to be in the tank accounting for displacement from liverock, heaters and other equipment and coral.