The water may look transparent, but it is made up of thousands of tiny particles that only the micro-pores of the filters are able to filter.
We use activated carbon with micro-perforated stone filters; we regularly maintain it for a maximum of three months.
When we do maintenance, the stone is filled with a slimy surface of the same color as yours. Lately, the water has been coming in much dirtier and with smells that are farther away from properly treated water. The same linen, when washed, is tanned by the sediment that the water brings.
At my brother's house in the country, Valencia-Carabobo in Venezuela, they use a couple of concentric tubes. The outermost tube acts as a first filter with 2 mm perforations, the second tube (internal), the perforations are 1 mm. Sand washed with activated carbon is placed between the two tubes. When I have visited him, the water always tastes fresh, my brother draws the water with a suction pump into a tank about 4 meters high.
Your brother is very inventive, I have a survival book kept in my emergency bag that is full of techniques like this just in case our infrastructure is destroyed by natural disaster that takes our electrical grid down. I expected the filter to be dirty but seeing what we might be drinking kinda grossed me out....
I read that most of our minerals used to come from water and clean dirt which isn't bad but now our sediment is full of farm runoff. Big factory farms use huge amounts of chemicals which are silent killers because they take a long time to build up in the bodies systems and eventually cause dysfunction and disease. Antibiotics cause disease resistant bacteria. That is what I am worried about, not dirt but industrial chemicals and fluoride dumped in our water which is from the manufacturing of aluminum. It is not naturally occurring fluoride, both are deadly if taken in large amounts, one is beneficial in small amounts the other from aluminum manufacturing accumulates in the body, ruining our very fragile hormonal system and causes brittle bones and bad teeth.
The practice of adding fluoride compounds (mostly FSA and occasionally sodium fluoride) to drinking water is known as community water fluoridation. It has been a mainstay of American public health policy since 1950 and continues to enjoy the support of government health agencies, dentists, and numerous others in the medical and scientific community.
As with many chemical additives in the modern world, however, few people know much about it.
Many are surprised to learn that unlike the pharmaceutical grade fluoride in their toothpaste, the fluoride in their water is an untreated industrial waste product, one that contains trace elements of arsenic and lead. Without the phosphate industry’s effluent, water fluoridation would be prohibitively expensive. And without fluoridation, the phosphate industry would be stuck with an expensive waste disposal problem