I hope you have the nitrate/nitrite numbers reversed...a nitrite of 3 ppm is extremely dangerous and unlikely as the fish would be dead.
To the cloudy water, this can be due to a few things. It can occur after a water change due to sediment in the source water (tap). The usual cause is a bacterial bloom, and there can be a diatom bloom and an organics bloom, all of which give the water a whitish haze or cloudiness. A green haze is an algal bloom. None of these are particularly harmful though they may indicate some other issue that could be if not rectified.
Water changes can help, but if it is a bacterial bloom it may not; but there is no harm, and much benefit, to any water change so don't be afraid of doing one. Provided the parameters [this refers to GH, pH and temperature] are basically similar and you use a dechlorinator/conditioner, no problem. The Safe Start may increase this haziness, but it is not harmful to fish so don't worry about using it but it should not be necessary and unless there is evidence of ammonia or nitrite I would not use it. [Again, assuming your nitrite is 0 not 3.]
Knowing more data about this aquarium might help us pin down the issue. How long it has been running, what fish and how many, normal water change schedule, additives, plants, etc.