I setup my 35gal 2 weeks ago...put 1 bala shark..3inches... Amonnia peaked, nitrite peaked...and they both at 0 now....Now nitrAte is between 12 and 25.
Your tank is cycled for ONE BALA SHARK. Each time you add fish you will have a "mini-cycle", so you will have to monitor closely when you add fish, doing the waterchanges as needed to keep the stress to a minimum.
The cycle starts with ammonia then goes to nitrite and lastly nitrate. Nitrate is the last stage of the cycle. From there either plants consume it as 'food' or nitrates get removed when doing a water change. You will have to keep an eye on the nitrates or get real plants to help lower the levels. Its a pain if your tap water contains nitrates. *thumbsupsmiley*