The rate that your nutrient solution flow is important in certain hydroponics applications. Commercial systems like Nutrient-Film Technique, may offer inqdequate or low nutrient flow rate. Insufficient nutrient flow rate may lead to root stress and disease.

Plants appear to utilize oxygen faster than any other nutrient in a solution. Good nutrient flow rate will allow oxygen to feed the entire root system. In systems like NFT, insufficient nutrient flow rate may starve plants' roots of oxygen.

Nutrient Film Technique is a primitive, but effective hydroponics system that was designed to improve the aeration of the nutrient solution by providing a thin film of water. However, due to the "slow" flow rate of the nutrient solution, the NFT systems channeled the solution, reducing the flow rate to areas where the roots are the most dense.

Subsequently, the root system in these "dense" areas become anaerobic, leading to reduced root respiration, reduced nutrient uptake, roots may become susceptible to infection and denitrification (to remove nitrogen or "nitrogen groups" from a compound) .

Conclusion:
To prevent denitrification, anaerobic, lack of nutrient uptake, minimized respiration and root infection, hydroponics systems should have an adequate nutrient solution flow rate and be highly oxygenated.