cycling question

So I had a 75 gallon reef about 6 months ago and I moved out of state I lost all of my coral during the move so I broke every thing down I have just now gotten everything back up my current setup is a 46 gallon bowfront with a 55 gallon sump. I used all of the old rock in my new tank. I did not boil or bleach I planned on using the dead stuff as an ammonia source. It has only been cycling for about a week now as of two days ago my ammonia was a whooping 8ppm on an api kit yesterday it was down to 6 ppm and nitrites were up some I think 1 ppm. Now today which is only the 7th day in ammonia is .25 nitrite is 0 and nitrate is .10 (nitrate is a sali feet kit others are api). So my question is what is going on? Do I need to add an additional ammonia source? Or are my kits jacked? It seems awful fast to go from 8ppm ammonia to .25 in just two days. And with the nitrates so low where did it all go lol?*



Btw I used 45 pounds of "live" sand (it was 45 pounds of dry sand and a small baggie of wet sea shells. Gotta love ebay)

And about 60 pounds of dry rock (previously live)*





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