Centipede is very picky on the type of fertilize and how much to use. What do you have for application? Spraying is best. BUT THE MAIN POINT is to use a Non-Chlorine based Potassium such as Potassium Nitrate. I've never seen this in a granular product. You need a 1:2 ration of Nitrogen Sulfur based such as Ammonium Sulfate (Not Urea) and Potassium as mentioned. Your pH should be more acidic which is difficult on coast with all of the shell deposit increasing the calcium in the sandy soil.
As far as weed control-you pre emergent such as "Gallery" would be better as it does not prune roots as bad as Dimension. Then post control of weeds depends on which you need to target. A good one is "Celsius" but not limited to just this one. Image, Certainty, Atrazine, Simazine, Vantage (Sethoxydim), Dismiss, Manor (Metsurfuron) all can be used safely on centipede. Just make sure you read those label and not over apply.
Centipede is a very nice turf and beautiful with the light yellow green color which some people try to make a dark green.
Just be careful and test your products. This time of year is not the time to start any fertilize but start looking into a winter weed control such as Atrazine/Simazine when it cools off--I generally wait until late October slightly before grass goes dormant. Watch you weather patterns for cooler weather. Pre-em about two weeks or so before green up and fertilize after two/three mowing after green up. Timing is very important.
Take a look at this if you can find it. http://lesco.johndeerelandscapes.com...source&ID=9996