Hi rank,

Of course to be sure, remove all heads in each zone and turn the water on in that zone. Flush until you see clean water from the farthest head. Hopefully you have good pressure so water makes it to the last head. If you don't have enough pressure to flush all your heads, then start replacing closest heads as they become clean. It is probably easier to just remove the last head and flush until clean and deal with individual heads that show spray pattern problems. Good luck. Aloha

Thanks Lehua, I'll try the furthest one away first. My biggest problem is I have to dig out the heads to gain access to the filters. Then the debris and sand flows back into the pipe when the immediate area floods out. I have use a threaded riser to keep the debris out. I wish there was an easier way.

Hi rank,

I don't know the type of you sprinkler you have, the filter is usually just below the screw-on nozzle. Try removing the whole head and screw in a threaded nipple with 90 degree bend attached to another nipple that flushes water away from your hole. That might work and it would be easy to make and install. Aloha.

Thanks Lehua, I'll try that. The hardest part is working in the Florida sun and humidity. I should've done it in the winter. Take care.