Help with cycling

Question
Hello,

You recently posted a question to Alex Kline in category Freshwater Aquarium:

Hello,

I'm currently doing a fish-in cycle with three fish in a 15 gallon aquarium. It has five live plants, two small fake plants and three terra cotta pots (which were cleaned prior to adding to the tank). Tank was seeded using filter media from an established tank and one plant also came from an established tank. The gravel was used in another tank but had been dried out/stored for over a year and was thoroughly cleaned prior to being placed in my tank. I'm using a liquid master test kit for my readings.

Day 1: Ammonia: 0, Nitrite: 0, Nitrate 0, PH: 7.4 (fish added late in the evening, test done a little later).

Day 2: Ammonia: 0, Nitrite: 0, Nitrate 0, PH: 7.4

Day 3: No reading taken

Day 4: Ammonia: 0, Nitrite: 0.1, Nitrate 0, PH: 7.4

Day 5: Ammonia: 0, Nitrite: 0.3, Nitrate 5ppm, PH: 7.4 (15% water change was preformed for the higher nitrite)

My question is: How am I getting a reading for Nitrite without a reading for ammonia? I did the test twice on day 5, as I was sure this could just not be correct and it was the same both times! Upon inspection, I discovered that my water condition neutralizes ammonia. Could this be that cause? Will my tank still cycle properly? As well, how am I getting a reading for nitrate on only day five of my cycle? Could the seeding really speed up the cycle this fast?

Sorry for SO many questions. This is my first experience with cycling and everything I'm experiencing seems to be going against everything I have read. The fish appear to be very happy. Still swimming and acting like they did the first day they were added to the tank.

Any help would be greatly appreciated.

Answer
Hi Michelle,

It looks like you meant to send this to Alex Kline, but you sent it to me instead - that's ok!

Seeding a tank with used filter media is extremely effective. Plants also carry quite a bit of beneficial bacteria with them, too. The best ones are Java moss and other such plants with a lot of surface area. I do this each time I start a new tank and within a month, everything is settled down and the water quality parameters are optimal. Within a couple months I usually fully stock my tank.

Keep testing daily for a bit, since nitrite is still toxic to fish, though by no means as toxic as ammonia. You should be out of the clear here. It's possible the dechlorinator is why you have no ammonia, but I think it's because your filter is already seeded. Your tank will cycle fine, just cut back on feeding since your tank can't handle much biological load until it's more mature. Stock slowly. Only feed once a day, or two very small feedings until there's 0 ppm of ammonia & nitrite.

The reason you're doing so well is because you used the best "bacterial starter" there is - established media! This inoculates your filter with beneficial bacteria, and it's your filter that contains most of the BB in your aquarium. Other methods, such as using a handful of gravel, bottled bacteria, etc. is a bit helpful - not much. Seeded media is the way to go, as your results prove.

Take care,
Nicole