Keeping the 4" to 2" reducer, Lowe's, as close to the pump's inlet as possible is best. Are you adding a union? If not at least get a Fernco so that you can yank pump when needed without cutting plumbing. Hint: 4" fernco is 6 or 8 bucks, 2" fernco is 4 to 6 bucks. Run 4" pipe to Fernco to 4 X 2 reducer bushing to male 2" to inlet on a 750. Coming out do the same thing...1 1/2 to 3" Fernco to spray bar.
3" spray bar is good. Remember you have to keep this little tub in one piece or your wife will bean you with a koi net like Gabby bops Joseph MBA.
