I am working a lawn with some serious issues. First off the customer skimped on the sod and got the cheapest deal in town so it is full of weeds. I have finally have them on the run, but the other problem seems to be a widespread yellowing. I know it may sound like chemical burn, but it isn't because I didn't spray parts that are showing the same discoloration and slow growth. I'm thinking it is an aeration problem. I noticed some ponding last time I was around when the sprinklers were on. Could it just be that? It is weird because the lawn goes from a nice dark green to a bright yellow and then back again in a matter of steps and there doesn't seem to be a pattern. What's going on?!!