At Aero-Stream I found a hard to find septic riser kit which has an adapter flange which will fit on my square septic tank openings. I chatted several times asking for help not only about their products, but concerning installing a Tee on my tank (it didn't have one!). The service agent was extremely helpful. I ordered two riser kits. The directions were a little sparse, but clearer after watching the video. There were a couple minor differences between the video and directions, but nothing too important. When I encountered an installation question, even though it was Saturday and the support staff do not keep regular hours my question was forwarded to someone who called within the hour. The only suggestion I have for their product line is an option to purchase masonry bits for drilling into concrete tanks. I would recommend two since one may wear our if you hit too many rocks. I highly recommend!