Yet another cycling question

[uihawk9868]

I am now about 4-5 days into a fishless cycle on my 20 gallon tank. I have been dosing the ammonia level up to 4 ppm. The day before yesterday nitrites were at 3 ppm. Yesterday they were at 10 ppm. ! Nitrates continue to remain at between 10-20 ppm. I am a little concerned with my nitrites being that high and it being so early in my cycle. Help is appreciated.

[Cliff]

What else did you add to your set-up, anything like some already seeded filter media ? Sometimes you can complete a cycle withing 3 weeks. As it takes the longest to grow the nitrite eating bacteria, you seam to be well on your way for a fast cycle.

For a 20 gallon tank, you likely could have started with a lower amount of ammonia, but that certainly won't hurt anything. When you start to get nitrites, you should maintain your ammonia level to about 1/2 of what you started out with, and only add ammonia when it drops to 0 ppm, but no more than once a day. If you started out with 4ppm, then you should now maintain the level at 2ppm.

[Stlouisfish]

+1 with Cliff - I am assuming that your nitrites were really high like that due to the excessive ammonia you have been putting in there - it's not necessary for that tank size - you are not trying to grow enough bacteria for a 50gal tank!

It appears your nitrites have spiked and are on their way down to 0 - I would take Cliff's advice and add enough ammonia to get a reading between 1-2ppm. The next day, since you have nitrites, add more ammonia (assuming it has already dropped to 0) - ammonia should not be added until you have a reading of 0.

By the time your nitrites fall to 0, you will probably need to do a large water change to get your nitrates down to 20ppm (it might be higher than your current reading by then).

Sounds like you are moving along quickly!