Fiberglass koi tank

[Gareth80]

I am new on here and are looking for advice. I have a 12ft x 4.5ft x 33inch deep tank and would like to make it bigger by increasing the depth and width is this possible to do

Kind regards
Gareth

 

[Meyer Jordan]

Not economically practical with fiberglass. Better to rebuild using 45 mil EPDM.