Ammonia fluctuating in a previously cycled tank.

Question
Hi! I seem to be having a problem with my tank.
I have been cycling a 20 gallon aquarium for about 1 month now. I was using the fishless cycling method where you add pure ammonia to cycle the tank instead of using live fish. Five days ago, the cycled seemed complete; my ammonia was down to 0ppm, my nitrites were down to 0ppm, and my nitrates were at 20ppm. However, around the time this happened, my 10 gallon started to have problems of its own, so I decided to plant it with an ornament from the cycled 20 gallon. The ornament, which was the only one in there at the time, had been in the 20 gallon since the start of the cycling. Also, I increased the amount of ammonia I added from 3 drops to seven, since I realized the amount I was adding before was too little, but the meter for ammonia stayed at 0. I then added 2 gouramis that measure around 2 inches each and later that day, the ammonia seemed to be climbing up to .02 mg per liter.
I'm really worried since this is odd for the tank to have been cycled for so long and then start acting up. Could me having taken out the ornament caused this?

Answer
Hi Andy, this is Nicole Putnam, answering your question from the question pool - where it was moved so other experts may view it.

I don't believe removing the ornament had anything to do with this ammonia spike, to be honest. Unless you have an undergravel filter, there's not much bacteria on the gravel, ornaments, or water itself. There's LOTS in the filter media, and some on plants (if they are live plants) but little on the surfaces...especially with a tank that is so immature. A month is not very long for a tank to be cycled, and it's probably going to be at least 3 months before your tank is stable. That's why for that amount of time, you should be very careful with what you stock and how much you feed.

The best way to cycle a tank is to take some filter media from a mature tank. You could have taken some out of your 10 gallon and put it in your 20 gallon. Ripping/cutting off some floss works if your filter media is the "cartridge" type. This will seed your filter with the beneficial bacteria that you need to cycle your tank.

The most likely reason your tank had an ammonia spike is simply because you added two new fish, which you probably fed once or twice. The load this created was too much for the immature tank to withstand - as the tank ages, it will develop more beneficial bacteria. Make sense? The best way to ensure you keep a colony of beneficial bacteria in your tank at all times, is to have biological media.

This can be a foam sponge, "bio fiber" or "biowheel" or it can be ceramic media. With AquaClear filters, the Biomax and foam sponges both perform biological filtration (Google for more info). Bio media is sometimes rinsed in aquarium water to clean it and remove debris - but it is never discarded, unless it becomes damaged or so dirty and clogged that it cannot be cleaned properly.

What you need to do now is do a water change. In fact, you will probably need to do 25% water changes 2-3 times a week just to keep things fresh and healthy. (You can use the dechlorinator Prime at a double dose, 4 drops per gallon, to detoxify ammonia while your tank still registers it.) Add a new fish or two each week until you're fully stocked. Feed little - two teensy meals per day, at most. A pinch of flake for two gouramis would be enough flake to fill your pinky fingernail, twice a day. You may find you are feeding them a lot more! You have to hold back with fish - they always act hungry and will beg for much more food than they should be having. As your tank gets matured, you can ease up and feed a bit more.

While your tank is newish, be careful when you clean the tank - don't vacuum too much gravel and try not to replace 100% of the filter media. Leave some of the old floss if it is time to change the cartridge. Some algae is normal and healthy - brown algae is common in new tanks, it's called diatoms (you can Google for more info). A snail such as a mystery snail will help keep your tank tidy, you can also try some corydoras - peppered cories are very hardy.

I hope that helps, take care.
Nicole