If you want to use a purge product, the best to get is Ahh-Some which is much better than Spa System Flush or Swirl Away or other products.

Even if a super-chlorination got rid of the white water mold (which in this case it didn't -- at least not completely), the flush product is useful anyway just to get rid of any greases or biofilm that may build up over time, especially if you aren't extremely diligent about maintaining chlorine levels.