Hi Paul, I hope you're well!....I have a quick question that might sound a bit stupid....due to evaporation from back chambers on my nano, I'm toping up daily at present and its always the 4 chamber, where return pump is and the one just before it; so chambers 3 and 4. Until this morning, I would pour water in there, the level would go up to where I want it and it would stay there....since this afternoon, when I put water in there, it comes up and then it goes straight back down again by 1/3 of the depth!!!...there is no water coming out of the tank; its dry all around it thank God, as we're away for a week from Monday so last thing I need is a leak right now.....so where the heck is that water going???? Any ideas welcome! Many thank; Enzo