Re: cloudy water
I suspect two different scenarios: Its either a bacteria bloom or a precipitation.
Bacteria blooms occur when there is a nutrient that is introduced that has been lacking. Sometimes the carbon sources can cause this. If bacteria haven't had enough of something, be it carbon, ammonia,etc, they cloud the water trying to consume it.
Precipitation occurs when you have an abundance of either a cation or an anion and then the other is introduced. This usually occurs if you have used a phosphate based buffer and then dose Iron.
I would test your phosphates to see where they are. If they are high you will need to do water changes to bring them down to a more acceptable level. If you have used a phosphate based buffer this can take a few changes. Phosphate should be maintained between 0.15-1.0 mg/L.
To clear the cloudiness you can either do water changes, use a clarifier, or wait it out. In both cases it will naturally clear up on its own but it may take a few days.