Question
We recently re-sodded our lawn due to a sewer line installation.  It is a small lawn in sandy soil in a house we purchased a couple of years ago.  The sodding was done by a professional and looked great for about a month, but now is showing sections that are turning yellow.  The lawn is on an automatic irrigation system that is daily for 30 minutes.  After the yellowing started I put a small amount of centipede feed and weed control brand fertilizer left over from last fall's application.  After two week's there is no sign of improvement.  Any ideas on what to try next?

Answer
My opinion is that the lawn may be over irrigated. I would gradually scale back on the irrigation until you can wet the soil down to a depth of six inches per irrigation twice a week.
Perhaps there is a spittlebug infestation.
Copy and paste the following to your browser and you will find useful information about your problem.
http://www.ugaextension.com/houston/anr/documents/CentipedeGrassTurningRedPurple...