As Tim stated in his earlier post, he needed to apply more than one application of Balan for any effective control. The reason Balan's effectiveness is reduced by sunlight. It must be watered in immediately after application. Balan has been around a long time and was marketed by Scotts. There are quite a few preemergent materials available today that are much better than Balan.
Pendimethalin is better choice.
My personal choice is Dithiopyr, the active ingredient in Dimension. Comes in a liquid or a granular. Excellent, relatively long lasting control, on many annual weeds with one application.
Regardless of which material is used, calibration of the application equipment is very important. Whether it be with a "hose end sprayer" or a rotary spreader for granular products. Apply too little, desired control not that good. Too much, it's expensive.
Also timing of application is important. It has to be in place before the seeds begin germination.
And one last point, preemergents control any seeds that will germinate. Not just weeds but grass, flowers, anything from seed.