Nitogen Cycle

[bruceanthony]

I'm fairly new to this, but I'm cycling a 30g tank. I used Caribsea instant aquarium substrate. It comes wet, packaged with live bacteria. You can supposedly add all your fish in 20 minutes, but I decided to just add a few and cycle first. There are currently 2 zebra danios and 2 neon blue dwarf gouramis in it. It's been a couple weeks since I started the tank. Ammonia 0ppm, nitrite .50ppm, nitrate 40ppm. Am I anywhere near the end of the cycle? How do I know when it's over? When the nitrite disappears? And once it's done, how should I go about stocking the tank? Like how many at a time and how often? Thanks for any tips!

 

[jlk]

The caribsea 'live' sand is claims to be full of live bacteria but its only intended for marine tanks. The bacteria in sw tanks is not the same as fw so basically you just added plain sand.

Based on your numbers, it sounds like your about half way through a fish-in cycle. Once you steadily see zero ammonia and nitrite with nitrates increasing, its safe to say your cycled. Right now, just stay on top of your daily testing and water changes to keep toxins at or below .25ppm. With .50ppm nitrite and 40ppm nitrate, I would do atleast a 50% water change to cut these numbers in half, possibly two wcs.

In respect to further stocking, wait for the cycle to complete then slowly add fish. For a small school, you can add them together at once. For a larger single fish, just one at time. After the new addition, continue to test daily and do wcs as needed. You may see some spikes in toxins. Once your tank has steadily stabilized again (1-2 weeks), you can add your next addition. Basically, it comes down to taking your time and stocking slowly to allow your good bacteria time to adjust to the increased bioload.

 

[bruceanthony]

That caribsea gravel was actually a freshwater version, so it supposedly had the right bacteria in it, but I had a guy at the local aquarium tell me the stuff's a joke. I guess it's apparent from the numbers that cycling is still required. Anyway, thanks for the advice! I'll get right on that water change.