Sequencing data size are different?

Theory behind mothur
#1

Hi, I just received my sequencing data. I followed same protocol for all sample while dna extraction. However it is not in same size. Also while analysis using Mothur some sample getting all commands run but with some samples Mothur showing ERROR “stability.trim.contigs.good.unique.filter.precluster.denovo.uchime.chimerasSCT-40-3_S37 is blank”. I am not sure about my data sequencing or it happen usually. Please let me know…

We used V4 region of 18S, using general eukaryotic primers

Sample Id Read Length (bp) Size
1 2 x 301 82 MB
2 2 x 301 216 MB
3 2 x 301 128 MB
4 2 x 301 125 MB
5 2 x 301 88 MB
6 2 x 301 21 MB
7 2 x 301 22 MB
8 2 x 301 284 MB
9 2 x 301 26 MB
10 2 x 301 107 MB

#2

This is completely normal. It’s not possible to pool samples exactly the same so you will get winners and losers of the pooling lottery-some samples just get more sequences as a technical artifact. You should rarify for analyses