Dear all:
When I use DADA2 to process my data with qiime2-2021.4 , I got very low non-chimerism. My sequencing platform is Novaseq. This is demux picture.
The command I use is
time qiime dada2 denoise-paired \ --i-demultiplexed-seqs demux-paired-end.qza \ --p-trim-left-f 0 --p-trim-left-r 0 \ --p-trunc-len-f 0 --p-trunc-len-r 0 \ --o-table table.qza \ --o-representative-sequences rep-seqs.qza \ --o-denoising-stats denoising-stats.qza
I got very low percentage non-chinmeric.

Why does this happen? Is there any way I can improve it?
Thank you!
Sincerely