Akeath

I've gotten some really weird readings today (day 35 of fish-less cycling). Yesterday my ammonia was at 2.0 PPM (I'd put 4 ppm in the day before yesterday) and the nitrItes were at 5 ppm. I was very busy that day, so I decided not to add enough ammonia to make the reading 4 ppm ammonia, and to add more later after the bacteria had eaten the 2 ppm ammonia it already had.

Today my ammonia was between 1 and 2 ppm, which is very strange since my bacterial colony has been consistently eating between 2-3 ppm ammonia every 24 hours, but according to these readings it had eaten less than 1 ppm ammonia in 24 hours for some reason! At the same time, I got a reading of 0 ppm nitrite, which would mean while the ammonia bacteria was eating practically nothing, my nitrIte bacteria had eaten 5 ppm nitrIte in 24 hours! What on earth is going on here? Is it normal for the nitrIte to drop this quickly? And why would my ammonia bacteria eat practically nothing? Was it possible that the ammonia bacteria was producing enough to make the reading of nitrIte 5 ppm just from its activity in a day, and since it hadn't been particularly active no nitrIte had been produced? But then, that can't be all of it because the nitrIte bacteria must have been active too, to eat the 5 ppm nitrIte already in the water...

As you can see, I'm very confused. Is there any reasons why this could be happening? Did I mess up my cycle? I am fairly certain there is nothing wrong with the test kits, as they are testing fine on my other tanks.

By the way, I went ahead and added enough ammonia to put the reading back to 4 ppm today.

Background info: I test with API test kits. I started cycling this 20 gallon tall aquarium 5 weeks ago, getting my directions from the add and wait method detailed on this site, here is the exact thread: 2 Ammonia methods of cycling your fishless tank. I seeded it with gravel from an already established tank, spreading the gravel across the bottom of the tank and putting a small handful in the filter. A week in, I saw the filter had stopped dragging in water, and I assumed that this had killed the bit of bacteria I'd placed in the filter. I of course fixed this, and have had no problems since (it was the intake tube). So, for practical purposes this tank has been cycling for 4 weeks with seeded substrate spread on the bottom.
On the 14th of this month (9 days ago) my ammonia reached 0. I continued adding in enough 10% Ace Hardware Ammonia - Janitorial Strength to read 4 ppm every day. My bacteria has consistently eaten between 2 and 3 ppm in 24 hours. Nitrites have been at 5 ppm for at least 2 weeks. Today is the first time it has read anything lower (let alone 0!)
Oh, and 5 days ago I put in 8 Bio-Stars into the filter, as extra media. This did not in any way interrupt the flow.

soldieroffortune1974

It's normal for the readings to fluctuate while cycling. What were the nitrate readings when tha Nitrite was 0?

1 of the reasons for maintaining a constant level of ammonia is to produce larger amounts of bacteria,if you stop adding that amount of ammonia,the bacterial colony will shrink (since there's not enough food source to maintain the larger colony)

Akeath

The NitrAte reading is between 80 and 160 ppm.
(There is no reading between 80 and 160, so I can't be very precise, but I think it is closer to the 80 end than it is to the 160).
That does suggest that the nitrIte bacteria really did eat all that nitrIte, of course. I guess what I'm confused about now is why it was so abrupt? No lowering at all and then in 1 day from 5 ppm to 0? Is that common?

I understand that the ammonia bacteria colony will shrink without food, but I've been extremely careful to give lots of food (ammonia). Yesterday was the first time I didn't put it up to 4 ppm. Never has it reached 0 since it went down the first time, and the colony was clearly not starved to death completely at that time, because it kept eating a large amount daily. And if that is what happened to my colony just recently, why would there be so much ammonia left? Wouldn't the colony eat all of the ammonia before it started to starve to death? It can't shrink by starving if it still had a substantial amount of food, right?

Lucy

I've found it's not unusual to get ammonia readings, nitrate readings but a 0 nitrite reading when I've cycled a tank with seeded material.
Whether the bacteria that converts nitrites to nitrates survive this transfer better than the bacteria that convert ammonia to nitrites, I'm not sure.

soldieroffortune1974

to me it sounds like you're nearing the end of the cycle process.Abrupt changes show that the bacteria is doing it's thing. You will likely have another abrupt change before the cycle is completed. That change will be No ammonia, NO nitrite and a high nitrate count. Sounds like you're almost there.It's common but without going into a long lenghthy explanation (actually search my threads and I think I already have )

ZomZom

I suspect it's easier for the bacteria to grab that top 2 ppm of 4 than to complete that last 2. That could be cause for some of the slowdown the day you didn't add ammonia.