If its going down then thats good. I also didnt fred my fish for two days to minimise further ammonia build up. This worked as my good bacteria wasnt fighting against added waste. Continue doing water changes, dechrolinate your water, stall feeding fish (this wont harm them).I don't know anybody besides myself that keeps aquariums. One of the local pet stores sells it per gallon but you have to figure out a way to transport it (he recommends multiple 5 gallon buckets with lids. Problem is I can't lift more than 2 1/2 gallons at a time - with my disabilities its just too difficult. Don't exactly live in the friendliest of neighborhoods. The only man in my life is my step-son but he gets abnormal heart rhythms if he exerts himself too much (I don't think he's up to carrying that many buckets). Plus this would only make sense if there was Ammonia in my tap water - which there isn't - so as long as I start with ammonia free water it shouldn't make a difference.
My little tank went from 4 ppm to .25 - then was back up to 2ppm today. To me that sounds like overfeeding - which I'm pretty convinced is what happened to begin with so I've cut them back to 1 meal a day (they hate me) to see if that helps. I rarely find leftover food debris but under and behind the foliage there could be some I'm missing. Early on I found 2 dead fish in one of my big tanks but that was the tank with the lowest ammonia reading at the time.