Moreover, it is not speak English is no problem, there is the Google Translator, I use also, otherwise I could not read your posts and not respond. He translated not always good, but it is to be understood.
I think that Günter Kopic so wanted to say that the number of bacteria (number of bacteria) can be kept very low with no setup, sand and leaves. High bacteria count = no or little pups.
I got about 20 years ago my first Paros by Günter Kopic and propagated since hundreds of Paros and even brought from Malaysia.
In a few species, for example, like now with deissneri and previously also in ornaticauda, I also have complete plants, leaves and ground away, just to the water parameters to control better and better adapt. But that is certainly not necessary. So far I could multiply all Paros, except deissneri with soil, leaves and plants