I bought this for my son's 8th Birthday and he was really excited about setting it up. Having read previous reviews i was unsure how successful it would be but followed the instructions very closely. We used bottled water with a low chloride level, put it under a lamp and waited - it wasnt until day 5 i saw something moving, it was so small if you blinked you would miss it. I decided not to skim the detritus off after a few days as instructed because i was worried i might loose the microscopic creatures in it! We are now on day 9 and 'Bob 1' (as named by my son) is now 1cm big and 'Bob 2' is 5mm and i have also noticed about another 5 tiny creatures moving about (they are about 1mm big) My son and his friends find them fascinating and i must admit i spend quite a bit of time watching them too!