| | Diatom Filters
I have the Vortex XL which is the heaviest duty one that I've seen. I think I recently saw it for $118 on-line somewhere. I think the diatom powder is $9 for 50# at home depot. I like the XL because the filter bag has a lot of surface area and the filter can take about 4 cups of diatom powder. This means that the filter works a lot longer without clogging and can clear the water quickly.
I've seen the filter bag for $19. It may seem like a lot of money but the last filter I bought I've taken care of and used for over 20 years. think my filter is about 21-22 years old.
The actual expendable filter material cost runs me only about $5 a year.
Considering the cost of a good motor, the special design of the pump housing, and the design of the filter bag, I would find it difficult for me to make a filter half as good as the XL for the same price as a new one.