it appears after numerous water changes and many newbie mistakes, my tank cycling has reset after 13 weeks. very disappointing and some lesson learned:
- added too many fish almost all at once (initially 2 goldfish, then 2 weeks later another 2)
- fed too much, and subsequently too much waste
- cleaned out filter and media with tap
- remove too many rocks/stones/decor, which inadvertently removed the growing nitrifying bacteria