Anyone use those black rubber fitting with hose clamps that slip over PVC pipe? I was wondering if the rubber would have any effect on the tank. They have a rather strong odor to them and might leach chemicals into the water. I have two of the 2" 90degree elbows hooked into the suction line of my closed loop for testing with freshwater before I commit and glue it up for good. Would be nice if I could leave them in permanently. They sure work good for taking up misalignment, vibrations, and allow for easy system breakdown without using unions.