I have posted a couple of threads but got no real info about what is going on. My tank has been set up for about 20 months and i followed the changing filter media by adding in a new one and leaving it to establish healthy bacteria and then i waited and did it to the other side (double HOB with biowheels) My water was doing great and was stable and I added several new fish, as the tank only had a pleco, a molly and some endlers. I added four fish at a time over about a week and all seemed well. Now my ammonia is up, it went from a stable 0 to a 1 and then after a PWC the other day it is down to 0.5 my nitrites are the darkest color on the test card today and yesterday they were the middle color (api sorry i dont have it handy) I am assuming that for whatever reason that my tank is going through a cycle but with the PWC's not seeming to do much I don't know if I should do them, or let new bacteria do its thing? The fish and snails seem fine, they are lively and active and using all three levels of the tank, the plants are also doing well. So should I just leave it for a few more days and keep testing? Will leaving the lid open help with off gassing? I am so frustrated and confused and I am scared that if I do too much the cycle will continue and cause long term issues for the fish and if i do too little I will kill them.... Advice please?!?