I use Seachem Flourish Iron and I have never noticed a Cloudiness resulting directly from Dosing this product. Although I have noticed if I dose too much of any of my additives I tend to get cloudy water.
What color is this cloudiness your observing? If it is green, could be that you have a free floating algae outbreak, which could mean you are overdosing your nutrients or your plants may not getting the other nutrients they need in order to out compete the free floating algae.
If it is white it is a bacterial bloom whereby there are so many bacteria being produced in your tank that you can actually see them, again it could be that you are overdosing on your nutrients or that your plants are being deprived of some nutrient in order to out compete the bacteria.
What is your lighting level and color temp? Also what is your co2, kh, ph, phosphate, nitrate levels?
An easy fix for all of this is a diatomaceous filter or micron filter used periodically, sometimes even though you are carefully monitoring your nutrient input you can still get these conditions and the filter will clear it up within hours, although I would not recommend using these all the time and it will not cure the problem long term you have to look at your nutrient balance for a long term fix.
You may want to wait for the older, more experienced members of this board to offer up their advice as there are some really wise people on this board who have far superior knowledge to myself.
29 Gallon Standard Moderate Light Planted tank
Lighting: 2x27 Watt 6500k P.C. Lights of America Outdoor Fixtures. 2x 20 Watt N.O. Flor. w/ Sylvania Gro Bulbs (9350k I think). Both are retrofited into a diy 12" tall canopy, with a 4" Diameter Clip on fan facing the opening in the back to circulate the excessive heat from the lighting.
Filtration: Tetra Tech 150 (modified to make very little disturbance.
Aquarium Systems Mini-jet for more circulation.