I've just installed an Eisbaer Pro Aurora 360 on a TR4 board (replacing yet 'another' failed Enermax LiqTech II AIO). I replaced the supplied fans with Noctua NF12 ippc fans. Temps at idle (29) and load (60) are excellent. The question I have is that the perspex window at the pump head shows an air bubble. This clearly isn't interfering with the pump or cooling. Is this an intended design feature to allow you to see that the pump is running (the bubble oscillates in the window when the pump runs), or do I have air trapped in the pump housing? The radiator is installed above the pump at the top of the case (a Phanteks Evolve X). All advice appreciated. Thanks.