Thanks for that super fast answer, yes, i understand! Well i was really wrong then!
And i did the same mistake for the alu rings, hopfully, i did not start to turn them! The inner diameter of the PVC tube is 219 and i bought O-rings type 200 X 5! I thought that the O-ring should be compressed (so that it had to be bigger) to insure a water tight tube! If i understansd i should buy something a little smaller as well. Do you have an idea of wich O-ring sascha uses? Sscha, if you read that post...
Thank you.