I am trying to help my neighbor re-pipe his above ground pool. It currently has flexible tubing, and the plan is to switch it to PVC. I am trying to find the correct union fittings for his pump and filter but have not been successful in locating them. The filter is a Hayward E-100 (sand), and the pump is a Pentair OPT-NI-1VD. The pump looks to have a 1.5" inlet/outlet. Can anyone point me in the right direction for this? I usually order from Amazon, INYO, eBay, etc.