Nitrites

My latest tank set up has a big piece of driftwood that I found by the river. There are somewhat soft areas at the core of it, most of the core is buried under the substrate. The outside is hard, well weathered and sun-bleached.
This is my 14th tank, and the first that I have had this problem with. This tank is more sparsely planted than my others. It has 3 jungle vals about 15 sag subulata, and a large willow moss covered rock. The tank is 30 gallons.
The filter on it had been running for a month in another tank before being placed on this tank.
My nitrites are about .25 ppm.
Nitrates are somewhere between 0 and 5ppm.
Ammonia 0ppm.
PH 7.4 ppm.
I am changing 10 gallons every other day.

How long has the tank been running?

How long has the tank been running?

Well the tank itself had the fish, the rock with moss, and some hornwort, as well as the filter for about a month. I added the substrate and driftwood a week ago.
This tank is a Walstad set up as are most of my other ones. The soil I used was from the same bag as I had done other tanks with. So far the soil has not come out from under the sand at all. Usually I get a little bleed through. It occurs to me that perhaps the beneficial bacteria in the soil also have not come out from under the sand?

You probably have too much decaying organic material for the filter to keep up with. It may not be done cycling, either.

You probably have too much decaying organic material for the filter to keep up with. It may not be done cycling, either.

Yesterday when I was changing the water the driftwood -which is not fully waterlogged, pulled up from the substrate and floated to the top. When it came up some of the soil under the sand came up with it. Today I have 0 nitrates, 0 ammonia, and 0 nitrites.
What I conclude form this is that:
1. My driftwood was not the source of the problem. Yay! It is still floating in the tank.
2. Having the soil perfectly buried keeps the good bacteria in it confined.
3. Filter was not fully cycled. Not sure why.

I never stop learning something from this process. Pretty sweet!