Water filter reduces water pressure

Hello,
I am new here and looking for advice on the following problem:
In my single-family house, there is very low water pressure on the 2nd floor. Showering is barely possible.
My neighbors do not have any problems with the water pressure.

As a test, I have now removed the filter paper from the water filter, which is located directly after the KFR valve.
Unfortunately, I don’t know what this filter is called: it is a plastic cylinder, approximately 1.5 liters in volume, inside of which there is a cylindrical mesh into which the filter paper is inserted. The water flows through the paper filter.

After about 2 months, the filter paper is completely covered with a rusty-colored, slimy layer. After replacement, the water pressure is only slightly better. Now I have completely removed the paper, and the pressure is much better.

My questions:
- What exactly is this disgusting deposit? Rust? (I have metal pipes, house built in 1989, very hard water)
- Can I simply omit the filter completely? (My aerators get clogged with limescale residues every 3-4 months anyway)
- The filter surely has its purpose, of course. Would it perhaps be advisable to replace the filter with a more modern one that does not reduce the pressure?

Thank you very much in advance for your help!!

Hello,

....In my single-family house on the 2nd floor there is very low water pressure. Showering is barely possible. My neighbors have no problems with the water pressure.

How high is the static pressure on the supply side? A filter inevitably causes pressure losses (reduction of the flow pressure), therefore there must be sufficient pressure potential on the supply side. If the pipe diameters are too small, partially clogged, or fittings are scaled, the available pressure potential is no longer enough to provide sufficient flow. The higher the contamination of the filter, the lower the flow. Possibly replace the filter with one that has low pressure losses => large filter surface! Completely leaving it out => dangerous, because this can cause clogging of the pipes or components of sensitive appliances (washing machine, dishwasher)! Apparently, there is considerable potential for this.
Best regards

Apart from the fact that it certainly makes sense to replace the entire filter unit with a more modern one, you should change the filter every 4-8 weeks. This releases a lot of dirt and increases the lifespan of the filter. We had the same problem in the previous house as well. At some point, there was hardly any water pressure upstairs. After replacing the filter unit, the problem was solved.

I have now flushed and tested the KFR valve.

After 3 liters of water, I stopped. Actually, the water should stop when the fuse trips. It doesn't take longer than 3 liters, does it? The main valve was of course closed (water meter was stationary during the test) and the valves for [UG], [EG], and [OG] were open.

Is my KFR valve defective?