As we all know algae is inevitable in both Marine and fresh water aquariums and if not watched and without proper procedures for removal can quickly turn a beautiful aquarium in to something that resembles a scene out of a old Swamp thing episode. Some are easy to control some are a non stop war. Once established either way the war against algae can be won with dedication and persistence. This is a easy a easy quick guide to the most common algae that plague us and basic steps we can take to control them through mechanical, biological, and natural herbivores. The dreaded green algae. Green hair algae: DERBESIA This is one of the most problematic Algae that is most commonly seen through out the hobby and is also one of the hardest to control once it is established and can be a daunting task to get under control and remove and will quickly take over your system if given the right conditions.. ID: This Algae is very easy to identify it forms green tuffs on the rock work and glass normally in areas of low flow it should be a solid green/brown color with strands of ( hair ) flowing away from the base. CONTROL: One of the easiest ways to control the spread and outbreak of this algae is to have aggressive skimming and control the amount of food you add to the system. This in conjunction with a regular water change and light use of carbon ( a good carbon ) will help you control the outbreak of this and many more types of algae. Also a Alkalinty of 8DKH or higher will help stem the development of this Algae. WHAT FEEDS THE GROWTH OF (GHA)? Green hair algae feeds off of phosphates as it primary source of food followed by nitrate's. So if you have a reliable pure fish food that is soaked and rinsed is one way to control the addition of phosphates to the system. Also the reason it is advised to not skimp on quality when it comes to activated carbon is that a lot of problems with algae outbreaks is caused by carbon re-introducing phosphates into the system after the carbon is used to its full potential. Also along with re-introducing phosphates a lot of activated carbons leach phosphates from the time they are added to the system. So Good carbon is a must to help fight Algae outbreaks. REMOVAL: A toothbrush is your best friend against this Algae and you should scrub the rocks with it after removing as much as possible by hand. NATURAL PREDATORS: This Green hair algae has very little natural predators ALGAE AGAINST ALGAE: A refugium is a natural way of removing Phosphates and Nitrates from your system. If done correctly a refugium can eliminate a lot of algae problems..Simple to set up and maintain all you need is a 6,500k light source And some chaetomorpha on a reverse or 24hr light cycle. This Algae will out compete other algae for nutrients and will not leach nutrients back into the system and will not go sexual..