Hi guys I'm new here. I've just started a plumbing comp in South Africa and going well till I was asked to change a toilet for a client and did and he's still got a flushing problem. It's a internal geberit system that flushes and all works fine. The problem is the water does not exit the bowl quick enough to take the toilet paper down. Ok so replaced the bowl not that. Thought the drain pipe was blocked so put rodes down and it's clear. There is no vent on the pipe so thought it was a vacuam. So put hole in just behinds the toilet on the 110 pile. No change in flow. This is how the pipes are done. Toilet on ground floor. Toilet to 90 bend. Then 2m drop, them 6m to go under a koi pond out side. Then junction to the main pipe and 30m to the septic tank. Running out of ideas. Any one have a similar problem.