Very Good Description, It translated very well into English. Not the Queens English mind you, but into the melting pot English we Americans call.. um... English.
OK, I see how I can help.
First off the soil seems to be ideal. The rich blackness indicates it is composed of organic materials and probably contains very little clay if any at all. Clay actually is a good thing and is often added to the soils, but we do want to avoild colloidal clay as it will stay suspended in the water column.
Second you stirred up a bunch of murky water by over-soaking the soil before adding the cap. You see, you added water to the soil and basically stirred it around (like making chocolate milk) when you added the swords. Then the dirt suspended in water rose though the gravel once all the water was added.
There are two competing methods to solve this. One is to add the top cap of gravel while the soil is still dry. You should use a deeper top cap of 1 1/2 + inches in the case of gravel.
The second is to wet the soil before adding top cap, but do not add too much water. The goal is to have the soil feel like a rung out sponge (soft, not dried out). You just want to re-hydrate the soil, not turn it into mud or muddy water. And give the soil plenty of time to soak up the water before you start to stir it or cap it.
Lastly you will have to do water changes if the water is discolored, and run a power filter (Hang on Back, whetever). Your water should be clear after just a couple changes and several hours of filtration.
Since this was a "test" tank are you willing to dump it and try to rehearse this again before moving onto the big tank?
I would like to hear the results of the next test.
I hope this made sense.