I fill it and nothing comes back out when I fill. I use a paper towel and squish the end and wipe the inside threads and the screw. Check the tank every so often and its wet on the bottom wipe it down, check it later and its wet again but i know for a fact its not the AFC or wicking. But anyhow like I said, just by putting that clear gorilla glue tape over the screw head I haven't had a problem but can see the bit of liquid sitting in the screw x. I'll try filling it slower and see next time. Thanks.