Water purification

https://www.offthegridnews.com/how-to-2/how-to-build-a-bio-water-filter/  This link shows a simple bio-water filtering system.  It is 3x5gallon plastic tubs stacked one on top of another.  The top one is filled with gravel, the middle with sand and the bottom with activated charcoal.  It actually reminds me of the water filters that I had in my aquariums!  This is probably the cheapest system I have seen but how effective is it?  I usually like things as simple as possible but for a water filtration system I am trying to look at multiple parts so that I have a backup.  I was thinking a 275 gallon ibc tote planted with water hyacinths might be a good preliminary filter, as well as a settling pond, though a settling pond would have to be bigger than the tote.  There are fiber filters that work well to screen out objects...diatomaceous earth..uv...RO...then the gravel, sand and activated charcoal...  Questions: does making this more complex make it more fool proof?  Open to any discussion here as to thought process and logic for setting up a water filtration system.  

For what use? For how many? What contaminates? Just drinking water for one, all household water for a family of ten, livestock? Starting from rain water, stream, well?

Don't do RO or UV unless you have to.  They both are high maintenance and fail easy. If you need near RO level of filtering for drinking, a Berkey does it simply.  There are cheaper versions, including filter kits made to work with five gallon buckets.  Daulton makes a filter to fit in regular plumbing, carried on Amazon.  Search for daulton rio 2000. It will remove anything living and chemical, but not quite fine enough for dissolved minerals.

Look at what earthship do for water treatment, they use gravel before the storage tanks and spin down self cleaning filters after plus the daulton for drinking water.  They do a good job on rainwater with very little maintenance or replacement filters needed.

I am looking at something to filter water for household use.  Yes, the RO and UV bother me.  Those are the suggestions I get on most other forums...so I turn to you, my partners in grime, for a solution that is maintainable :)  If winters were not so cold where I have my land, I would consider user water plants as a prefiltration system.