I don't know that tank at all, but some things to check:
1) Are all the O-rings forming a proper seal, and are you sure you didn't replace one while changing it? (Tanks will often come with diagrams of what goes where and spare O-rings in case that happens... It's not uncommon).
2) Is there a part you think you might not have screwed in tightly enough? If so, do you have thoughts as to where? Everything should be tight, but not so tight that you'd break anything by screwing it down further.
3) Did you check that your coil was tight in the mod.... Is it a new coil and that is why you were washing your tank? Make sure that it is a hair tighter than finger tight, is what I usually do. Easy enough to remove with a bit of pressure, but definitely snugly seated.
4) If it's a new coil, could be that you have a coil that isn't good. Sometimes there have been QC issues with smok coils, and they can cause leaking and flooding. If everything else looks good, you could try another coil.
Best of luck with a solution.
Anna