One of the most commonly found problems in the hydroponic system is that of salt blockages. Usually, salt and minerals are present in the nutrient mixture you fed your plants on. This means that the salt will start gathering when the growing media faces an increased evaporation rate.
The growing container is continuously flooded and drained. So, in some cases the draining part takes place a lot faster which means that the nutrients the roots absorbs have a slower rate of absorption. In other words, the water evaporates, while the minerals remain on top of the growing bed. Furthermore, the electrical conductivity is increased, which will lead to abnormal activity in the root zone. This extra amount of salt can interfere with the osmosis process. Adding up, the direct contact with the plant, will lead to lack of nutrient absorption. Summing up, salt build ups act as a barrier between the plant and its natural processes.
It is an event easy to spot and you do not have to be an expert to decide whether or not you are facing a salt problem. Usually, you will be able to notice a white crust on top of the growing media. Keep in mind that there are several growing medias that favor the appearance of salt. One of them is the rockwool due to its porous surface. Also, there are specific systems more prone to this. Take the ebb and flow hydroponic system: the continuous flooding and draining process can leave the plant unable to process all the water that goes by. This means that nutrients are left behind on the surface of the growing media.
The first sign of a salt gathering is the fact that the growing process is slower. Another sign is the fact that your plants will get darker and darker and lose their natural color. There are advanced cases when even the roots present some signs like burning spots.
So, in treating this solution you will have to make use of a solution that contains certain nutrients. It is recommended that this flushing process to be done monthly in order to prevent the salt to gather on the surface. If you have a system that has an increased evaporation rate, you will have to clean the container more often.
In conclusion, for a healthy hydroponic system you will have to closely monitor the effects of the nutrient solution on the growing media. There are several cases in which the evaporation is so fast, that the nutrients do not get absorbed. Experts say that you should dress the salt problem as soon as you have spotted it. Leaving it as it is can cause permanent damage to your system.