How old was it when the motor went? I don't like chlorine, I'd be inclined to use Epsom salts and just change the water every few weeks.
They stated it was a build up from the chemicals used if I remember correctly. They repaired the motor but at folks expense. That was the reason I chased for details on what chemicals to use but they were not forth coming, the email above was the last in a series of emails of me pushing them but all followed the same pattern of avoiding giving specific details, it started by me asking what to use as they they had no list for sale on their own site, then they added a page later but has been out of stock since added. So based on listing you should use chlorine granules.
Did they say how they determined it was chemical damage? If it's under warranty then you should insist they sort it, you could actually argue it's not fit for purpose if it can't handle chemicals that are necessary for it's use.
RIP Wilson ;(
That's one big echo dot