You said that Petco tested the water for you, does that mean you don't have a test kit at home? I would highly recomend the basic liquid test kit for fresh water, it will last several years and give you a great insight into your tank. During the first month you probably want to test your water every other day so you can change water if the Nitrates get too high.
Also, adding Stresszyme helps cycle the tank faster by adding good bacteria. Even after the tank is established I use it during water changes to help prevent sludge build up in the rocks.
Do you have any live plants in the tank? That is very helpful because it uses the excess nutrients and helps add oxygen to the water. The roots dig through the gravel and help prevent bad bacteria from building. Plus, it gives the fish places to hide and rest so they are less stressed. I think my fish have brighter colors and live longer living in a tank with live plants. I recommend anubus as a hardy, low light plant. I still have my original from when I started with fish well over 10 years ago. They grow slowly, but they are very sturdy. Be sure if you are buying plants they are true aquatic species and not submerged terrestrials, they will just end up rotting under water.
I loveee it!
