Help advice needed

[mOnsterzOas26]

Heres the story my cousin just set up a biocube 29 gallon 2 weeks ago , he used live rock , new sand seeded with a cup of established sand , so heres my question evrything was doing good till 2 days ago he got huge bloom of some sort of green algae on sand glass rocks corals on basically everything , at fist I tought it was cause of his light schedule he was running the lights for About 16 hours dayli, so I told him to cut off to 8-10 hours dayli , yesterday we did a water change clean sand and glass and he got a clean up crew so eveything was looking clean again but today , the green algae came back , so my question it's what could it be and how to battle it , thanks in advance

 

[Tahoe61]

If your water source is RODI and you do not expect elevated nitrates or phosphates then the initial algae bloom should clear on it own with the help of some snails (after the initial cycle). Not unusual to see an algae bloom in such a young tank. You could tell me to just leave the lights off for another week.

 

[mOnsterzOas26]

Thanks for ur help