I'm new here and relatively new to fish! Last Sunday I bought a betta and cleaned out a 10 gallon tank that was given to me by a friend. I set up the tank with a heater and a filter. I did some research on the cycling process and bought a master test kit. I've tested my water every day since Sunday. I have a 0ppm ammonia reading now after having *maybe* a .25ppm reading for 2 days. I never got a nitrite reading but I did and still get a nitrate reading of 5.0ppm when I test my water. I'm wondering how I have a nitrate reading when I never saw a spike in nitrites first?
Also, I'm not sure if this information is needed but my pH is 8.4 and I performed about a 20% water change on Wednesday. I added some aquarium salt with the water change because I think the little guy I bought had/has some fin rot going on.
I do want to add some tank mates at some point but not until my tank is healthy. Any advice for starting up a new tank, why I would have a nitrate reading when I never had a nitrite spike or tips on treating fin rot would be extremely appreciated. Thank you!