Yay my tank is beautiful and clean now :thup: I syphoned up the gunk on the bottom (which is really easy as it has no substrate) and slightly repositioned my Windelov log, and did a 50% waterchange, repositioned the filter outflow and added some Flourish Excel. My fish were looking very happy when I'd finished, and the Emperor Tetras were chasing each other up and down the tank. They are so beautiful to watch, because their colours seem to 'flash' when they swim really fast, and they have lovely little neon blue eyes