Check your incoming water pressure 50-56 psi max. If ok perhaps the arrestors you installed are to small or full of water. Try installing an air colume ( homemade water hammer arrestor. Its just a long vertical pipe with a cap on it. perhaps install some sort of drain to rid it of water. I have built such devices using 2 inch galv. pipe 3 feet long. NO MORE HAMMER. This klarge of unit was used on an irrigation system Had several bought arrestors that failed. Kept blowing out pressure gagues. Try installing air colum at entrance and one about mid point in plumbing system. Doug in the woods