BioSevia is used very well alone in soil, (2 ml / L with each watering). A small amount of BM can be added to facilitate the decomposition of organic matter and improve crop performance.
In hydroponic cultivation, however, it is always necessary to use BM because it is necessary to reproduce, in the nutritive solution, the process of natural decomposition which is done in the earth.
How to use microorganisms?
In the water, their living conditions are not very comfortable because they do not have around them the buffer capacity of the soil to protect them from sudden changes in temperature or pH. They also need to "fix" and can not survive and multiply simply over the course of the current. They need a very oxygenated place and must remain wet. Dry, they die.
There are 2 possibilities:
You use a wet substrate such as coconut fiber, rock wool, etc. In this case, you can inoculate the substrate directly with the micro-organisms. Simply sprinkle BM on your substrate.
You grow in bare roots or on a very draining substrate like the ball of expanded clay or pozzolana. In this case, use the BioFilter. It will provide your micro-organisms a place where they can reproduce.
Use 10g / 100L of nutrient solution. Add it every 6 to 8 weeks
Whether in the BioFilter or in a substrate, microorganisms do not generally pose a problem as long as their environment is oxygenated and moist. It is also good, to protect them, to avoid any abrupt change in their environment, be it temperature or pH. The more numerous and happy your micro-organisms are, the better your plants will be nourished.
Warning: a significant drop in pH is an alarm signal that indicates with certainty the death of a large number of organisms. In this case, you have to find the cause, treat it and reseed.
BM and SubCulture eliminate pathogenic fungi in the roots and break down organic matter in the nutrient solution. SubCulture operates especially in hot weather. If you already use SubCulture, you do not need BM.