Thanks so much for the tips everyone, its solved all the problems. This really is a great forum. My partner and I feel like idiots because we still cant figure out what the heck the little black plastic thing does (there's a photo of it in one of jennybugs 'Marine Tank 3 -The Edge!' pics, the...
taking the lid off seems like the only I can fix the noise problem too, would love to know if this will cause any problems in the long run (leaving the lid off)
apart from that very happy, spent hours trying to find my 6th endlers guppy when we found it had been sucked up and into the filter :(...