Every tank gets algea as it matures.
To get rid of it, either you chemically get rid of it or fight a loosing battle of tweaking all the stuff experts tell you to do.
There are two things the algea needs. Light and nutrients. The nutrients either comes via food for your fish or what you have in your tank and the waste that breaks down into nitrates. You take out one or the other then the algea will die.
Since you cannot take out all the light from the tank you do the next best thing. Take out the nutrients, which should be done anyway.
These nutrients are ever present until your tank matures and is able to take care of itself.
The best course of action to a tank that already HAS an algea problem is to cut back on introducing the nutrients to the tank and let it drop, THUS you have less food for the algea to grow and it will DIE off itself, without much molestation of the tank itself either by hand or by chemical.
All this is just a minor inconvience to your eyes. It isn't going to hurt anything in your tank.
Or you can nuke your tank and give the algea a form of over the counter red algea mustard gas. ((Ultralife Red Slime Remover)), which I found rather effective as well.
I'm not talking about prevention here and yes, each tank gets loading until the eco-system takes over on it own, but immature tanks don't have a decent eco-system built up.
The best thing to do is to keep your nitrates under control all the time, but not everybody does and thinks like experts, thus nutrients get carried away and algea blooms come and go.
There are other ways of preventing algea to grow in your tank such as using Cheato or Mangroves to eat those nutrients out of the water to lessen your nitrates and phosphates, which the algea feeds upon.
You could cut back on your lights, but I would say give the algea what it wants and it will become a glutton and eat up those trates or phosphates and eventually it will die and disappear, but you'll have to make sure you vaccum it out when it is gone and it will have eaten up all the extra nutrients which caused it to grow in the first place.
Typically, the phosphates will come from your fish food, or from some sources of water. If you use frozen foods, rinse your food first then put it in the tank. Also, try to feed once every other day.
You should test your water for phosphates, before you put it in your tank as well as for nitrates to ensure that you are not supplying this, however, most systems do not have a lot unless you live in an area with a lot of agriculture run-off.
Nitrates come naturally from the tank through the nitrogen cycle and food waste breakdown. Thus, why it is stated to feed only once every other day to keep this down. Make sure that you have a large enough cleanup crew, not only to clean algea, but to eat the leftover food. Other ways are to make your own food suppliments.
Eventually, your tank will mature and the symbiosis of the live rock and all the little critters in your tank will aid in cleaning out the extra nutrients out of your tank water.
lion_crazz. I don't mean to argue with you, but I'll bet you have just a bit of red algea somewhere in your tank as well. It is just a matter of how low you keep the nutrients from letting the algeas get the upper hand as nothing ever really disappears.