Advice on a "new to me"

[untamed]

re: no Nitrate. If you are detecting ammonia, it suggests that you've lost some of the bacteria. At this point, don't go cleaning the sand or overcleaning the filter. Go slow. You may not be seeing any nitrate yet, but that is because the ammonia has to convert to nitrite first.

Watch that ammonia level. If you are lucky, existing bacteria will ramp up quickly enough that you'll only have a "mini-cycle". If not, you'll need to do some water changes to keep that ammonia below toxic levels while the bacteria colonize.