Catheter issue

I’ve had a supra pubic catheter for over 10 years but get regular sediment buildup. Any advice, I think it may be infection related but does the infection cause the sediment or the sediment cause the infection?

I’ve had a supa pubic for the last 3yrs, mine gets changed every 8 weeks and I take Ascorbic acid tablets [one a day] to stop it getting scaled/blocked. The nurse who changes it also told me to twist the tube daily to stop it getting ‘stuck’.

Thanks, I’ve decided to see a urologist privately so hopefully he’ll be able to help but thanks for your reply