Swimming Pool Sand Filter Systems in Spain and Portugal – how do they work?

https://www.youtube.com/watch?v=w_J5KgIqhD4&feature=emb_titleWe occasionally get asked about swimming pool sand filters from people who have never owned a swimming pool before. Apart from the lessor used diatom√°ceos earth (D.E.) filters there are two basic choices for pool filtration systems which are sand filters and cartridge filters.In Spain and Portugal it is far...