Greetings! I have a 75 gallon planted fresh water tank, that started out in a 53 gallon tank. While it was in the 53 gallon tank (which ran for about 2 months), the aquarium appeared to cycle just fine. While in the 53 tank the nitrite levels were 0.00 ppm, Ammonia 0.00, Nitrates would run around 5 to 10 ppm. I did a fish in cycle method, with 6 Prestila tetras, some shrimp and 1 Cory. When the tank cycled and was still reading zero on ammonia and nitrites, I added 6 bleeding heart tetras and 1 additional Cory, the tank was still running fine. During this initial setup, I was doing 30 % daily water changes, sometimes maybe skipping a day. My wife and I decided to move everything to a larger tank (now the 75 gallon) we moved all the substrate ( made up of bags of aqua soil, aquarium gravel and then a layer of sand on top) and added an additional bag of aquarium sand on top for the additional space of the 75. We then moved all plants and fishj, shrimp etc to new tank and then topped off the tank with additional treated water to make up the difference. I assume I have crashed my cycle since now, I originally had some ammonia showing up around .25 to .50 ppm, and nitrites were running around .25ppm, and nitrates around 5.0ppm. I have been doing daily water changes and adding stability to aid in bacteria growth. I now show 0 on ammonia, Nitrites are are creeping up to around .50 to 1.0 ppm and nitrates are around 5.0ppm to 10ppm. The nitrites never seem to go down even after water change, which I have been doing 30 to 40 % water change daily because I was scared of the nitrite levels. My tap water does not register any nitrites when I test it. Any help would be greatly appreciated. I am just wondering if the tank just needs to cycle again? I feed pretty light (once a day) and only enough for the fish to consume during the feeding. Plants seem to be doing fine and have bounced back since the move. Let me know if you need more info. Oh! My ph has always been around 7.2 to 7.6 throughout the entire time, with the exception of at very first the ph dropped to around 6.8 to 7.0 during the brief ammonia spike after the move. Current readings as of this morning, after a 30% water change last night. The pH is 7.2 to 7.6 range, ammonia 0 ppm, nitrite .50 ppm to 1.0 ppm (seems to be creeping up), Nitrate 5.0 to 10ppm. I should mention that originally I was running a Tidal 75 on the 53 gallon tank, then moved it to the 75 gallon tank and added a new Fluval 407 to the 75 gallon tank. All original bio media was moved and placed in the Fluval 407.