# Post Run Automatic Purge for NextSeq 500/550
The purge option appears when the run stops prior to completion (eg, due to a clustering failure). Select **Yes** to commence purging of the reagent.
**Estimated time for automatic purge**
* The time for automatic post-run purge completion depends on the length of the sequenced run and the type of kit used. This can take between 15 minutes and several hours.
* The purge duration depends on how much left-over reagent remains in the reagent cartridge.
* After the purge, a post-run wash will automatically start (90 minutes).
* Users can expect the purge + post run wash to take between 2-5 hours.
**Additional notes:**
* Users can choose to opt out of the purge, however a manual post-run wash must be performed prior to setting up the next run.
* There is an option to set up an automatic reagent purge after each run, to purge unused reagents from the reagent cartridge to the spent reagents container automatically after each run. For further information, see the [NextSeq 550 System Guide](https://support-docs.illumina.com/IN/NextSeq_550-500/Content/IN/FrontPages/NextSeq-550-500.htm).
\
\
\
| |
| :--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------: |
| *For any feedback or questions regarding this article (Illumina Knowledge Article #1971), contact Illumina Technical Support* [*techsupport@illumina.com*](mailto:techsupport@illumina.com?subject=Question%2FFeedback%20Regarding%20Illumina%20Knowledge%20Article%20#000001971%20-%20Instrumentation%20\&body=Dear%20Illumina%20Technical%20Support,%0D%0A%0D%0A)*.* |
---
# Agent Instructions: Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.
Perform an HTTP GET request on the current page URL with the `ask` query parameter:
```
GET https://knowledge.illumina.com/instrumentation/nextseq-500-550/instrumentation-nextseq-500-550-reference_material-list/000001971.md?ask=
```
The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.
Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.