smallRNA GAIIx raw fastq files - quality filter?

[vebaev]

Dear all,
I have raw fastq files and I want to do with the help of FASTX toolkit:

1.fastq to fasta
2. clip adaptors
3.collapse to unique sequences

But before that I;m not aware what quality filter to apply to the fastq file in order to remove not quality entries/sequences (probably with fastq_quality_filter sub-program)?

Or if not FASTX do you know what tool to use to make quality filter run and the default option for smallRNA-seq?

Thanks!!!