I am installing an outdoor shower against one room of a house. I used plastic pipe. I am having problems tightening the the plastic pipe to the shower unit. The first time I tightened too much cracking the joint. The next time I tightened nice and snug and it leaked. The last time worked but I had to snug it up almost as tight as the first try. Of course, the first leak went unnoticed in the wall for a week, ruining some of the new hardwood floor. Is there some other system that I should be using for shower units?