How to Cycle an Aquarium Properly (NZ Guide)

Luca Toal

⭐ How to Cycle an Aquarium Properly (NZ Guide) — The Way I Actually Do It

Cycling a tank is one of those things people overcomplicate to death. If you’re new to fishkeeping, you’ve probably Googled it once and immediately closed the tab because it looked like a chemistry exam.

Here’s the good news: cycling is easy. Seriously. You just need to build the right bacteria in your filter so your fish aren’t swimming in ammonia. That’s it.

This is the exact method I use at Simply Fish and on customer setups. It works, it’s quick, and it keeps your fish safe — especially when you use products like Seachem Prime and Seachem Stability, which make the whole process way smoother.

🌱 Alright, So What Is Cycling?

Think of your tank like a new house with no plumbing. If you add fish before the plumbing exists, everything backs up and becomes… well, not great.

Cycling builds that “plumbing”—the beneficial bacteria that convert toxic ammonia → nitrite → nitrate. Once those bacteria colonies are established, the tank basically maintains itself.

⚡ The Simple, No-Nonsense Way to Cycle a Tank

Here’s the method I stand behind:

👉 Treat the water with Seachem Prime
👉 Add Seachem Stability (this does the heavy lifting)
👉 Add a few hardy fish
👉 Keep dosing Stability daily for the first week
👉 Test weekly until ammonia and nitrite hit zero (Use high quality test kits)

That’s the whole process. No magic tricks. No waiting six weeks for your tank to “find itself spiritually.”

🧪 Step 1: Add Prime — Don’t Skip This

Prime is the only dechlorinator I trust. It removes chlorine and chloramine and detoxifies ammonia and nitrite for 48 hours.

That detox buffer is exactly what makes cycling with fish safe.

If your ammonia or nitrite bumps up during cycling:
👉 dose Prime
👉 everyone survives
👉 bacteria keep multiplying

Easy.

🧫 Step 2: Add Stability — The Stuff That Actually Cycles Your Tank

Stability is full of the right bacteria your tank needs. Dose it every day for the first week and your tank will cycle dramatically faster.

No joke — I’ve cycled tanks in under two weeks using Stability. Regular cycling takes a month or more.

Just follow this:

  • Day 1 to Day 7: Dose Stability daily

  • After that: Once a week, or anytime you add fish

It’s pretty much automatic after that first week.

🐟 Step 3: Add a Small Group of Hardy Fish

You don’t need to throw 20 fish in at once. Start small.

Good beginner fish for cycling:

Add more fish slowly over a few weeks. It gives your bacteria time to catch up.

📊 Step 4: Test Once a Week

Don’t overthink it — just check ammonia, nitrite, and nitrate.

The cycle is complete when:
✔ Ammonia = 0
✔ Nitrite = 0
✔ Nitrate = 5–40 ppm

If ammonia or nitrite ever show up:
→ Dose Prime
→ Dose Stability
→ Retest in 24 hours

That combo keeps everything safe while the bacteria settle in.

⏱️ How Long It Actually Takes

Without products? 4–6 weeks.
With Prime + Stability? Most tanks settle in 10–14 days.

I’ve never seen a tank fail to cycle using this method.

❌ Common Mistakes That Make Cycling a Nightmare

These are the things that slow everything down:

  • Rinsing your filter media under tap water

  • Adding heaps of fish in the first week

  • Replacing your filter sponge (never do this during a cycle)

  • Doing massive water changes for no reason

  • Not using a proper bacteria product

Avoid those and your tank will cycle smoothly.

🧼 A Few Luca Tips

These are the little things I see help people the most:

  • A small sponge filter + your main filter = more bacteria = safer tank

  • Cloudy water during cycling is normal — don’t panic

  • Only clean your filter if flow drops, and even then use tank water

  • If ammonia creeps up, Prime works like a safety net

Once you’ve done this a couple times, it becomes second nature.

🎉 Final Thoughts

Cycling doesn’t need to be stressful. With the right products and a bit of patience, it’s honestly the easiest part of fishkeeping. Seachem Prime and Seachem Stability make the process faster, safer, and simpler — especially for beginners.

If you’re ever unsure or want help checking your water, come see us at Simply Fish. We do this daily and can get your tank sorted quickly.