What can I use on my lawn? Help please. I have Tex Turf 10 Gr.?

My family and I moved into a house in March. The gr was beautiful and we were told it was called Texas Turf 10. It;s a very thick, lush lawn that needs to be cut short and looks like turf. I know from reading the small amount of information online that it doesn't need a lot of water at all. But over the summer, my lawn has been overrun by weeds and is very light in areas. I know it's that time of the season that lawns begin to turn yellow (I live in West Texas) but I was told that the lawn stays green throughout the year and when we were looking at the house before buying in February, it was green. I've found a lot of the weed killer, fertilizer, etc on the market doesn't work on this gr and I found that it actually made it worst. Does anyone have any suggestions? My wife has spoke to some green houses and they've gave some suggestions, but I wanted to come on here and see if anyone has this type of gr and what they use on it. Thanks in advance!