Refinement of the reverse osmosis filter

Once, during a hot summer, my wife drew my attention to the strange taste of water that flowed after the filter. We had a three-section flow filter installed under the sink, and for drinking we also used an additional filter in the jug.

Although the filters under the sink were changed not very long ago, I decided to change them again, and to my horror I saw an unsightly picture, something like this:

And since the filter flasks were not transparent, it was impossible to see all this horror in advance. And despite the fact that I was guided by the manufacturer’s recommendations on the timing of filter replacement, the surprise came out very unpleasant.

After that, it was necessary to take care of obtaining clean water, which is used for cooking and drinking. Only this time I decided to think before thoughtlessly following the recommendations of manufacturers and following their advertising communications.

And to my displeasure, I did not find such an offer that would suit me! As a result, after some thought, I decided to slightly modify the reverse osmosis filter, which I want to talk about.

As you already understood, I decided to replace the old filter with an installation with reverse osmosis – a semi-permeable membrane through which only water molecules pass under pressure, and all impurities merge into the sewer. Such filters provide probably the highest quality degree of purification, only their price bites.

Reflections on choosing a new filter

As a rule, filters with a reverse osmosis membrane are offered for the home, which have from three to five cartridges – several pre-filters, a reverse osmosis membrane and a carbon post-filter, the price of which ranges from 8 to 20 thousand rubles.

If we were talking only about a one-time purchase, then you can pay such a cost once, but replacement filters also cost money! And they change several times a year (the reverse osmosis membrane is a little less often – once every 1 – 1.5 years). And the cartridges in the filters need to be replaced every 3-4 months (a set of replacement cartridges costs 1-3 thousand rubles), which looks a bit ruinous.

And although they don’t save on water (and health), I was interested in the question why do almost all manufacturers have two carbon filters in front of the reverse osmosis membrane for pre-filtration? After all, they are of little use, since the degree of purification by the membrane is much higher. And then it dawned on me, consumables! After all, if there are pre-filters, manufacturers force them to constantly change, although by and large they are of no use!

The real benefit is probably only from the fine post-filter, but even here it’s not all that simple. In most cases, post-filters are made in a separate small housing, in which not the cassette is changed, but the entire filter as a whole! And this also does not affect the reduction in the cost of consumables.

But since such solutions do not benefit the consumer, then the manufacturer is probably interested in them, right? After that, everything fell into place and the next plan was born to refine the filter in order to reduce periodic costs without compromising consumer properties.

What do I want from a new filter?

• Since each manufacturer wants to bind the consumer to the use of only their products (incompatible seats or element sizes), such manufacturers are in the firebox. You only need to buy a filter that uses standard and widely used consumables (for example, 1812 reverse osmosis membranes).

• At least for the first coarse filter, the flask should be transparent so that you can visually control the degree of its contamination for timely replacement.

• Since for a reverse osmosis filter two preliminary carbon filters are needed like a dog’s fifth leg, I decided to switch one of them to work as a post-filter, and throw out the regular post-filter with a non-replaceable cartridge. But here you need to choose carefully, since some manufacturers make cases in which you can’t change the order of connecting filters (as in the picture below)!

The result is the following connection scheme:

Connecting the filter connection sequence before reworking:

Connecting filters after rework:

The right flask in the photos has been switched to work as a post-filter. The whole work took about 5 minutes (I was looking for a fitting to connect two tubes longer).

Final result:

The results of measuring the mineralization of water. Tap water, jug filter water, and reverse osmosis membrane filter water.