@Alvin Alejandro Don't add GFO.
You just have some algae growing. Not a big deal unless it's something other than regular algae. Buy some snails to keep it mowed.
As long as the tank stays balanced, corals will grow and use a large share of dissolved nutrients, with algae "drinking" the rest. Keeping this balance takes very consistent, regular dissolved nutrient levels AND feeding rates.
The goal
should not be to starve the algae out. Why? Because
sometimes starvation seems to work.
Sometimes it doesn't work.
Sometimes it leads to
things worse than green algae. (
@Whipples is totally on the right track!!)
There are better strategies anyway.
Normal algae is an
ally in maintaining a healthy system – not an enemy – so why take a hostile approach? Right?
If there's something wrong with the tank and (e.g.) you're getting uncontrolled blooms of algae, or algae won't grow
at all, etc – those kinds of things do indicate problems. But nutrients and algae are not one of them....nutrients are required for everything to grow, repair and divide, and algae keep the tank healthy and are food for many organism.
So the question is what
is the problem, if any?
- Too many big changes to the tank?
- Too few grazers?
- Lack of phosphates?
- Lack of nitrates?
- Some other nutrient imbalance?
- Inconsistent feeding methods?
- Inconsistent water changes?
- All of the above?
- Some of the above?
- Something else?
Just a few causes to be on the lookout for.
By far not an exhaustive list!
Keeping the tank balanced can sometimes mean needing to add some nitrates or phosphates to make up for minor shortcomings. With enough consistency in your system, any need for that should be small and temporary.....but it's important to know about and not ignore.
This might be helpful:
A Nitrate Dosing Calculator For Better Tank Health (And Better Coral Color!)
If interested, make sure you click around in the
Algae and
Nutrients sections as there is A LOT of great info in there. Holler back with any questions!