Hi, I'm new to ponds and Koi. My husband just built us a pond in April. I'm loving this new hobby, but it is more complicated than I expected. My pond is 12X5 and over 4 1/2 feet deep. I put 3 koi in and the pond cycled and everything went back to 0. It took almost 5 weeks. So I added the last 3 koi and they have been in there a week and the pond is now showing 0.25 of Nitrite and maybe 0.25 of ammonia, the nitrate went back up to 5.0. Was this supposed to happen? Will the pond cycle everytime you add a fish? I don't plan on adding anymore, I'm just confused. I have a aqua uv bio filter a performance pro pump, and after being obsessed with this site the last few weeks or so I had my husband build a 100 gal skippy filter with a rubbermaid stock tank. I don't know if adding the stock tank with the 100 gal of water made everything go up again because of the new media or what. Also at the top of the skippy filter I went out there today and saw a BUNCH of baby snails, I have no idea where all of these things came from, but will it be okay? Do I need to attempt to scoop them out? I know i'm rambling just so excited to be able to ask somebody for some help!! So Hello and I hope I don't bug you all with too many questions!