I recently moved into a new home with an existing sprinkler system. Due to the unusual amount of rain in the past year here in central NC, the previous owner didn't really need to use it much. We're just now getting enough dry days strung together for me to get the system fired up. Got around to testing it out over the weekend, but not all of the heads are popping up because of the density of the soil and grass. (tall fescue). Any tips to locating these easily? It's easy to get a general idea of where the heads should be, but other than poking around with a screwdriver not sure what else to do. I wasn't able to find the few remaining small heads.