[kittygilchrist]

The red stuff is clay fill dirt. It packs down easily and water stands too long. I water alternate days from neighbors to lessen perpetuating swale problems.
The corner lot where trucks parked nearby had to be specially aerated and top dressed. Top dressing with black kow or other organic material is always a good idea.

But, when you get Lloyd's expertise, you will know what the real issues are. Also, you might want review zoysia care by googling uf site for it. Much of it I see is scalped..Also, with grass that is fairly established letting the lawn dry a bit between watering will encourage root growth. Best fertilizer is 8-2-12.