Thanks for the link I downloaded the info last night

You are putting it down weekly?? How much per application (1lb for every 1k sq ft)? My lawn area is right at 36k sq ft so I had been using 3 bags of the Lesco fert which covers 45k. After looking at Bermuda bible it seems I have been calculating wrong. My biggest issue is this thick black clay under the sod! I have been using sulfur twice a year And there has been some improvement just slow going. I have less thin areas but the overall green of the lawn is just not there yet.
I have read that Bermuda does well at low cutting height but I have not had the nerve to cut mine down to 2 inches. My mower is set at 3 1/2 during the cutting season and just before going dormant I go down to 2 1/2 followed by the first two cuts of the season at 2 1/2. From what I have read it seems to be encouraged to cut at higher grass height during the heat of summer.
Bottom line is I’m determined to get this lawn healthy!! THANKS...