HELP!! Bacteria bloom!

[Tux]

SO ill start with what equipment i have.

Biocube 16 deleted lid
Ai Prime 16 HD
Jabao OW-10
Random protein skimmer from an old tank. Bought it off of facebook but i have it fit (Tight fit) in the first chamber.

10lb bag of carrib sea live sand.
Live rock was from my old tank that I just let dry out so its dry rock I guess??

LIVE STOCK - Two clowns. One hammer coral. Small frag of Zoas. And a kenya tree.

Tank had been running for about two and a half weeks. At first it was cloudy I guess like usual but some what cleared up. I used seachem prime and not sure if that was a good idea? I also used API quick start. The time came this weekend to do a water change so I did and this morning i woke up and it was cloudy as can be. I can barley see through the other side the tank!! Whats a good way BESIDES UV sterilizer to clear this up? Another water change? Running my skimmer?
Adding more Quick Start? Siphoning the sand? Thanks!!!

EDIT. Also i forgot to add i added one clown yesterday and the hammer. Two snail. AND a piece of live rock thinking it would help me with some beneficial bacteria.

 

[Spare time]

Did you cure the old rock? A cheap temporary all in one UV sterilizer is really what you need