If your ammonia is still above four you have more water changes yet to do. It would take 4 50% waterchanges done in one day to bring that ammonia down to a safe .25 reading. After yoget the .25 reading today test again tomorrow to see how many waterchanges you will have to do daily.

If you have common or comet goldfish for long term plans you need to be looking into a pond for them to live happily in.

Good luck.