Sash Balance Size?

A quick learner from Cincinnati, Ohio says:
Bought a house which was a flip of a flip. While trying to repair this double hung window (will have others to follow) it looks like I've come across a sash balance that has been cobbled together with pieces. The tube itself is 28 inches long with a 5/8" diameter, but the spiral itself fits completely inside of the tube with a blue tip. The outer (top) window may have a 25 inch tube. We've already purchased a 3/8 tube at 28 inches, but when installed, the window couldn't completely close. Help?
Thumbnail of the uploaded file named 20200905_151050.jpg
Profile picture of Bob
Bob from SWISCO responded:

The diameter of the outer tube is what counts here. If it's 5/8", then it sounds like you need an S600-28 Spiral Balance. This comes with a Blue Tip option. Let me know if you have any other questions. 

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)
Current wait time is 4-7 business days
We promise that one of our experts will personally get back to you as soon as they are able. Thank you very much for your patience and understanding. If your inquiry is time-sensitive, please feel free to reach us at 856-317-6263 or at