What Smith-Root eDNA filter pore size should I purchase?

5µm - For studies targeting fish, amphibians, mammals or other metazoans, we recommend using a 5µm filter. This filter pore size allows microbes and fine sediments to pass through the filter, preventing it from clogging prematurely. 5µm eDNA filters work well in a wide range of sampling habitats because they deal well with variable levels of turbidity. These filters work with all Smith-Root pumps including the eDNA Autosampler which only functions using 5µm or greater pore size.

0.45µm - For studies targeting microbes, we recommend 0.45µm filters because they capture the majority of microbial taxa. These filters are prone to rapid clogging, and they do not work well with the eDNA sampler backpacks because the maximum filterable water volume is often less than the minimum sample volume for the sampler (0.5L). For 0.45µm filters we recommend the Smith-Root eDNA Citizen Scientist pump which does not have a minimum volume or minimum flow limitation.

1.2µm - Our third filter pore size 1.2µm, is suitable for low turbidity environments and studies targeting a wide range of taxa (including fish and other metazoans). These filters will also capture many microbes, but they may capture more metazoan taxa than 5µm filters when the water turbidity is very low. These are suitable for the eDNA Sampler only in low turbidity habitats, and they are not suitable for the Autosampler. 1.2µm works well with the eDNA Citizen Scientist sampler in most environments.

A note about eDNA capture on filters. For a given amount water (e.g., 1L), smaller pore size filters will always capture more eDNA than larger pore size filters. The advantage of 5µm filters over 0.45µm filters is only measurable when more water volume is filtered through the larger pore size. 5µm filters are the most popular Smith-Root eDNA filter product because a significant water volume can be filtered in most aquatic habitats.