Our liquid sand filter cleaner is a fast-acting formula which will restore the efficiency of your swimming pool sand filter. However, by using liquid sand filter cleaner before backwashing, you can eliminate built up contaminants for a much cleaner filter. And a cleaner filter will, in turn, result in better filtration. When you simply backwash your sand filter, you will only succeed in removing larger debris and contaminants while smaller debris particles such as oils and minerals will remain in the filter, continuing to build up over time. As this occurs, your filter's ability to function properly will decrease.