New in ground install. 8 x 7 h5ot tub. 6 jets around perimeter and 2 in the floor. Designed to be used with a single 1.5hp silencer blower. Since day one the bottom jets have not worked. The layout is such that almost immediately out of blower two lines are run to hot tub - one for 6 perimeter jets and one for 2 floor jets. We installed a manual valve in the line for the 6 jets and closed it and the lower bubbles work just fine. Slowly open it and get bubbles out of all 8 jets. Set it and forget it and come back 45 minutes later and no bubbles out of lower jets again. Have to close valve, force air to lower jets, and then slowly open again. We tried a 2hp Silencer blower and no change. The pool company has never seen this before....the plumbing company showed up - saw that we already installed a valve and said, "you need two blowers". Absolutely not. I have pics of the plumbing and there is some 'questionable' elbows in a line to the hot tub - cannot tell what the line is to though. My though is obviously excessive back pressure in the one line. Thoughts / ideas?