This DIY version does not have the same pre filter as commercially available ones, and would need to have the filter changed more often at a minimum. There are

This DIY version does not have the same pre filter as commercially available ones, and would need to have the filter changed more often at a minimum. There are studies showing the success such as this one. https://www.ncbi.nlm.nih.gov/pubmed/9192919 https://www.ncbi.nlm.nih.gov/pubmed/9192919