Algae are not really a bad thing, but most aquariums are far better without it. To better understand, here is why algae exists and how you can manage it to avoid problems.
Nitrate, phosphate, carbon dioxide and dissolved organic matter are substances that accumulate in your saltwater aquarium providing the main source of survival of free floating algae.
Nitrate is the first source of life for algae. We have discussed that nitrate is a by-product of nitrite decomposition in your saltwater aquarium.
Phosphate will be present in your saltwater when you do partial water change. Excess food that your inhabitant did not accumulate will also be present. You cannot avoid phosphate but you can control it.
Carbon dioxide will always be present whether you like it or not! But some sources of it can be avoided.
Then the last component comes from the dissolved organic matter.
Installing a protein skimmer will help in algae control. There are tons to choose from in the market.
If you want to learn more information about protein skimmers, I wrote an article about them over here.
It explains on how it works and a comparison on brands
Another helpful solution will be to add some inhabitants in your aquarium that cleans algae like snails. I would recommend one of our vendors, Saltwaterfish dot com, if you plan on getting some of these cleaner snails in your tank. They offer free shipping on snails. Just use code FREESHIP at check out.
Excessive amount of these nutrients leads to algae outbreaks in your saltwater aquarium. It also needs light to thrive.
There is really no single simple maintenance technique on how you can avoid algae growth. But knowing which ones and how much are good will help.
More information about algae and algae types on this page.