Conventionally, we use fertilizers to increase pH. Typical components are Potassium Hydroxide, Potassium Carbonate, Potassium Bicarbonate, and Potassium Silicate. We must consider, just as with adding pH down components, the nutrient value of these products. Ensure the Potassium PPMs are accounted for and do not cause any antagonism with other nutrients in the solution.
Further to that, we must consider the buffer capacity. Buffers are pair molecules of acids and their conjugate bases, commonly phosphoric acid and phosphates. If we have overly buffered solutions, it can retard plant growth due to ion antagonism.
We characterized buffers by the pH range over which they can maintain a more or less constant pH—the more pair molecules in the buffer solution, the greater its buffer capacity. Having a large buffer capacity in the solution can maintain stable pH levels; however, too high can affect chemical interactions and nutrient uptake efficiency. Therefore, getting the capacity right to maintain stable pH with minimum ions in solution is critical for optimum nutrient use efficiency.