Brian Knight wrote:Run your outlet, supply lines and all related fittings as big as possible to improve pressure.
No, they don't have to be sealed.
If I want to run directly from the downspouts to the tank do all seems need to be well sealed in order to get a good gravity feed?
Brian Knight wrote:Wouldnt restrictions in supply lines hurt pressure?
I think you may want a pump but it would be nice to avoid it.