Details on how I make NSW are near the top of the page here....
http://www.lostmymarblz.com/reeftips...ottomtanks.htm
It is possible that the venturi is adding bubbles to your water making it appear cloudy. Also, you can't just dump in salt and expect it all to mix. Some salt will fall to the bottom of the mixing container and stay there unless you go to the trouble of getting the powerhead into all the nooks and crannies of the container.