+1 on the garage door thing , I was also wondering about debris from outside falling into the tank
I would be worried about toxins from grass fertilizer , pesticides , exhaust fumes ect... (maybe I just worry too much
) I saw another thread where a guy had to run a house size a/c as a chiller b/c the tank was in the garage. I am sure you have thought of all this , I just hope we don't need to have a telethon to help you Finnish this project!
OOOO I forgot to say............GET TO WORK!!!!!!!!!! GEZZZZZZZZZZZZAAAA