I had a small garden pond with 2 small waterfalls installed in my back yard 21/2 years ago. It leaked then and the company came out a apparently fixed it temporarily. They found several leaks, one being from a seam they glued together. The past 2 summers, there have been problems with leaks and they came out and tried to fix them. This spring there was a bad leak. The water level dropped about 6 inches in 2 days. I called them again and they wanted me to do some troubleshooting, which I did. It still leaks. One of the things they had me do was loosen the fittings in the "well" so the pressure from the pump is not so high in the waterfall and it "relaxes" the system as he said. He says this lowers the pressure and keeps the water from spilling over the liner in the fall. It seemed to slow the leak but now the check valve won't stop the water when I have to turn the pump off and when I do this all the water from the falls drains to the main pond and into the overflow. When I turn the pump back on I will have to add 2-3 inches of water that I lost. Sorry about the long history, but here is my question. It seems to me, if the system was installed properly, I wouldn't have to loosen the fittings and allow all the water to go over the overflow. My pond is not that large (about 80 sq ft) and I think they should have used one piece of liner instead of gluing 2 together. Does anyone know if this is a common practice.