We have just moved into a house with an indoor heated pool with liner. The liner is around 10 years old. The previous owner drained the pool and we have now refilled it. Initially everything seemed ok but when we were away on holiday I turned the heat off and during that time several large creases have appeared in the liner. The pool has a brominator and water test results are.
Bromine: 1 ppm
Calcium hardness 140
Could turning the heater off cause the liner to crease or is it simply the liner is old or is there any other possible causes ?