I think I know what Jim's response will be:
In my best Jim voice:
Because it is so difficult to estimate how much time each part of the aquarium will take, it is impossible to assign a percentage of completion. What I mean by that is - he could be *almost* done - and get hung up on one tiny detail that could take a huge amount of time to finish. ....or, feel that he is about 99% done, yet that last 1% takes about as long as the 99%.
Of course, I'm often wrong - so he could be typing up a post right now that says he's 80% done. ...maybe I should just keep my mouth shut.