I'm running two bubble bars off of one Top Fin AIR-8000 pump, which has four air outlets (so I have "bridged" two outlets with a "T-connector" to feed one bar, and did the same with the other two outlets) and I noticed that near the area where the air actually pumps from the outlets, the sets of airline tubing down there have turned a heavy, almost alarming yellow-ish color that I assumed was from the constant pumping of the air into the tubes...is this just oxidation staining and are there any dangers?