You can buy double sided adhesive seaming tape ( aquaticeco.com ) that is specially made for EPDM linersto join them together.It cost about $ 1.00 a foot if you buy 100' roll. I am using it without any problems. I also recently bougt 15 x 50 EPDM 45 liner for my 7000g indoor pond and paid $ 400 with the delivery from a Supplier in Ohio - not bad.