You'll need to use Right Start with every
water change to make the tap water safe by removing the chlorine, chloramines and detox heavy metals.
Stress Zyme is said to contain bacteria. However, it's the wrong kind of bacteria, that's why you have to keep adding it. It dies quickly.
It can prolong the cycle by using the
ammonia the beneficial bacteria needs to develop.
I'd suggest you stop using it and save yourself some money.
Keep a close eye on your water parameters, it might send you into a mini cycle until the natural bacteria catches up.
Do water changes if you get any ammonia readings.
Don't feel bad, it's very confusing. When I started I got sold Stress Zyme too....a lot of us did. I still have it lying around here somewhere. lol
If you cycle your tank without it, the only thing you'll need to add is a good conditioner such as Right Start, Prime or Stress Coat.