Green Algae Issue in Sand

[CoralNoobDude]

Morning reef community. I've been having a 2 month issue now with a green algae breakout in the sandbed of my tank. The picture attached to this post does not fully depict what has been happening. This picture is 4 days post a 50% water change and 3 day tank blackout. The tank looked clear of this green stuff for all of 10 hours. Now is coming back.

So it always comes back spotty then grows and covers the entire sand bed (I have a sand substrate not crush coral). Eventually it covers the rocks as well. Its thick and dark forest green colored. And I want it out. I know it wont be an overnight process but please help.

Tank params:
Salinity: 1.25 or 35
Tempv 78F
Nitrate: 10ppm
Phosephate: 0>0.25 ppm
Ca: 460 ppm
KH: 8>12 ppm

Water is crystal clear... no cloudiness or evidence of excess nutrients

 

[vetteguy53081]

Not abnormal especially if a newer tank.
Reduce white light intensity a little and add snails:
Turbo
Nassarius
Astrea
Nerite
Trochus
6-8 blue leg hermits

Are you using RO water or tap water from faucet?

 

[CoralNoobDude]

Not abnormal especially if a newer tank.
Reduce white light intensity a little and add snails:
Turbo
Nassarius
Astrea
Nerite
Trochus
6-8 blue leg hermits

Are you using RO water or tap water from faucet?

RO water...small protein skimmer and small sterillizer

 

[vetteguy53081]

RO water...small protein skimmer and small sterillizer

Is your tank at or near a window?

 

[CoralNoobDude]

Is your tank at or near a window?

Not near a window...but on the first floor in house in foyer. So it does get some indirect light but the tank faces north-east so never any direct sunlight. That said, I've taken the white spectrum completely out of my daily light cycle and Ive notice that the richness in color of the green colonies has diminished greatly. And my coraline colonies are beginning to spread a bit faster. Nov. 1 the tank will be a a year old. Fingers crossed it begins to look much better and I'll begin adding more corals.

 

[vetteguy53081]

Not near a window...but on the first floor in house in foyer. So it does get some indirect light but the tank faces north-east so never any direct sunlight. That said, I've taken the white spectrum completely out of my daily light cycle and Ive notice that the richness in color of the green colonies has diminished greatly. And my coraline colonies are beginning to spread a bit faster. Nov. 1 the tank will be a a year old. Fingers crossed it begins to look much better and I'll begin adding more corals.

Indirect sunlight does have an impact due to uv rays. Try blocking that side with black construction paper and see if its a fix