# Library loading concentration considerations for the iSeq 100 On the iSeq 100 the loading volume for all library types is 20 µl. | Library type | v2 Loading Concentration (pM) | v1 Loading Concentration\* (pM) | | ---------------------------------- | ----------------------------- | ------------------------------- | | 100% PhiX | 100 | 60 | | AmpliSeq for Illumina Library PLUS | 50 | 50 | | Illumina DNA Prep | 100 | 200 | | Illumina DNA Prep with Enrichment | 75 | 100 | | Nextera XT DNA | 150 | 50 | | TruSeq DNA Nano | 150 | 100 | | TruSeq DNA PCR-Free | 100 | 100 | | Illumina DNA PCR-Free | 120 | N/A | For other library types, 50 pM is the recommended starting loading concentration. **Important note:** The above recommendations are general starting points. Optimize concentrations over subsequent runs to identify a loading concentration that consistently yields data that meets run specifications. This information can be found in the [iSeq 100 System Guide](https://support.illumina.com/downloads/iseq-100-system-guide.html). \*v1 reagents for the iSeq 100 have been discontinued, but the information for them remains here to assist labs still finishing their v1 inventory. \ \ \
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