Thanks, Valveman. I heard from the mfr for the corrugated hose & they said they hadn't tested nor could they recommend using it for a suction application. So, it looks like I'll have to go with the option using the rigid stainless steel pipes & deal with elbows. I wish I knew what the outlet size was on the holding tank. It looks like it starts out larger then reduces then gets larger again. But it could just be bc of the couplings making it look that way. I'll have to take a good look at it in the daylight. I wonder if long sweeps would be less restrictive on the flow and/or if I should try to angle it so I can use 45s instead of 90s.