HELP- 24gal NANO Tank

Hi

My son started a small saltwater tank, I believe it's called a NANO tank.
A all in one tank.

Well the water has turn all green, and cloudy. You can't see to the back of the tank. the tank is not very old maybe 2mos. the water sample that he has taken to the lfs for testing come back good, he work at the lfs. Everyone that he talk to can't help him.

So he ask me to ask you for help!

Tank is 2mos old, it has lr, plus about 1 1/2" of ls. when he got the lr from the lfs. in side the rock hiding was a yellow fish, sorry i don't know what kind of fish, the tank is at his moms. well he though that was cool that the fish lived. so he got more thinks, i think 2 more fish, and soft coral.

I was tell him to go slow but what do i know!?!
He has done a bunch of water changes, but with no luck.

CAN YOU HELP HIM????????????

 

did something die in the tank? maybe the coral? do you have any pics?

 

he said that nothing die in the tank.
and sorry i can get the pic small enough to fit.

 

Do you have a skimmer? What is the flow like in the tank? I would scrub any remaining algae in the tank and continue to do water changes.

What lighting are you using, and how long are the lights on for?