Final answer:
To turn the filter on or off for a BLASTX search, you must adjust it in the algorithm settings. This setting is fundamental to honing the search and getting relevant results by avoiding low complexity or repetitive sequences.
Step-by-step explanation:
If you want to turn the filter on or off for a BLASTX search, you perform this action in the algorithm settings. The filter in a BLASTX search is used to mask out segments of the query sequence that have no significant similarity to sequence database entries, avoiding issues with low complexity or repetitive sequences that could lead to misleading or irrelevant results. Therefore, to adjust this filter, you would need to access the algorithm settings where you can specify the parameters for the search itself, including whether to use a filter.