Hi. I recently got a Betta about three weeks ago and have done a water change before with no problem. I just did another 15% water change, which I'm doing weekly. I also cleaned the gravel which let a lot of waste/debris fly into the air. I have one real plant in the tank, and I also changed my filter cartridge today because it was making some strange noises. I noticed when I got home that the water is a bit cloudy, which I looked up and many said it'd disappear in a few days. However, my nitrite level is at a 5 and I'm really unsure how to handle it. Nitrate is at 20 ppm which is good for freshwater fish. pH is at 6.5-7, the KH and GH are both good as well. I'm not sure how I'm supposed to get that Nitrite to go down though, and I'm really worried my fish is suffering because of it. I've heard of "Prime" but everywhere I looked didn't give me much information so I'm here asking for help. Please give me some answers, I don't want my fish to be suffering! Sorry, I should also mention that he's swimming around normally. He likes to swim around when I sit in front of the tank, but when I'm not around or on the other side of the room he's more laid back and likes to relax by a plant or the filter. He hides behind the filter but I added a pantie hose so he wouldn't get stuck. He doesn't get stuck, he just likes to hide behind there to sleep and such. I'm not sure if that's important but I decided I should mention it.