One application of fungus control will not kill the fungus. You need multiple applications 2 weeks apart. Also important is what time of day you are watering. If you are only watering for 15 minutes (which is not really long enough to get water down in the soil) you should be able to water during the early morning so the grass has a chance to dry out. Does the fence shade the spot? Can you eliminate watering that area?

I will need to double-check the sprinkler system. I had it serviced when i moved in but that was really to just make sure all the heads were working and i'm not entirely sure all areas are being equally covered. I currently water every 7 days but have watering restrictions where i can only water on wednesday / saturday every week. In this scenario perhaps I should water on my allowed days, then take one off? That way i am watering 3x every 2 weeks - pretty close to the 5 day schedule.

Watering: Deep and infrequent is the mantra for watering. This is for all turf grass all over the place. Deep means 1 inch all at one time. Put some cat food or tuna cans around the yard, and time how long it takes your sprinkler(s) to fill all the cans. Memorize that time. That will be the time you water from now on. My hose, sprinkler and water pressure takes 8 full hours to fill the cans. Your time will likely be less. I like gentle watering. As for watering frequency, that depends on the daytime air temperature. With temps in the 90s, deep water once per week. With temps in the 80s, deep water once every 2 weeks. With temps in the 70s, deep water once every 3 weeks. With temps below 70, deep water once a month. Note that you have to keep up with quickly changing temps in the spring and fall. This deep and infrequent schedule works in Phoenix and in Vermont, so it should work for you. The reason for deep and infrequent is to grow deeper, more drought resistant roots and to allow the soil to dry completely at the surface for several days before watering again. If it rains, reset your calendar to account for the rainfall. What is important about the wnf product is the herbicide used in it. Just because it says it is safe for southern lawns, does not always mean it is safe for St Augustine. Bermuda is a bullet proof southern lawn that can take all the herbicides EXCEPT the one designated for St Augustine. That would be the atrazine based herbicides.

I laid 9 pallets of sod about 4 weeks ago. The grass is mostly looking great, it gets plenty of water and is rooting itself well. However 4 spots have started to brown. They're about 2 feet in diameter and all in fairly close proximity to one another. The photos don't really show the contrast well, the spots are more profound in real life. Any thoughts?