I live in central FL. i have a commerical account that has bahia in the front entrance. About 800 sq/ft. Over the last 3 months it's been thinning and filling with broadleaf weeds. I've seeded with 10 pounds of seeds and sprayed 2-4d herbicide with no luck at all. The owners want it thick and money isn't an issue for them. Any professional advice would be greatly appriciated, thanks.