Filter Cleaner with pH colour indicator
Filter Free removes rust, scale, oil and fine particles from the filter that back-washing fails to remove. You can tell it is working by the distinct colour changes. For effective cleaning and scale removal, the solution is red. If you have insufficient amount dissolved in the water, the solution will be a yellow orange.
For a thorough cleaning, dissolve 500g of Filter Free in a 20 liter of lukewarm water.