Third spiral balance broken!

A quick learner from Florida says:
This in the third window that has broken the spiral spring. I am wondering if the sping is too weak? Its a 3'X5' single hung tilt window and its dual panes.

Also the actual spring (wrapped in a plastic tube which is shattered whe the spring failed 3/8" tube) measures 33.5" (top of the balance to the end of the metal exposed sping). Should I use a 34"? see the photo
User submitted a photo of a window balance.
Profile picture of Paul
Paul from SWISCO responded:
Hello! I believe your hardware will match our Series 900 spiral balance. We use metal tubes, which don't burst like the plastic ones tend to. As for the length, if you got 33-1/2" by measuring from the end of the tube to the end of the exposed spring, then I recommend our S900-34. I recommend weighing your window sash to confirm which of our Tip Color options is best.
Reply to Thread
Use this form to ask a follow-up question or to share your experience regarding this subject.
(your email address will be kept private and is only used to inform you when a response has been made)