help! think i messed my cycle up..
 

I've got a 55g that has been cycled for 5 months. Decided I needed more gravel and added 35lbs ,covered up existing gravel only stirring very slightly as it was colored gravel and I wanted most of it covered up with black. Anyways ammonia and nitrite went up to. 25 ,I did a 50% water change and it took care of it. Will I be fine now or is this something that can go on awhile. I also added 4 different live plants the day I added gravel.

The Bacteria that we need in aquariums to process the waste from fish, is found in the filter, and a large amount can also reside on first few centimeter's of substrate.
By covering up the old substrate,you may have smothered the bacteria which need oxygen to survive.
So long as you did not also replace the filter material at same time,the bacteria will establish itself once more on the substrate but it may take a few day's.
Would monitor the water with test kit to see that ammonia or nitrites did not become elevated (water changes) and would perhap's not feed as much for a few day's .;-)