Maintaining the proper pH in the stream of your hydroponic system prevents a negative chemical reaction to fertilizers within the irrigation lines. A high pH level can often cause blockage within the lines and result in serious problems for your hydroponic system. pH stands for "potential hydrogen" meaning the concentration of positively charged hydrogen ions relative to negatively charged hydroxyl ions in a substance. Hydrogen ions are of course acidic in nature while hydroxyl ions are basic, keep these facts in mind both as you build your hydroponic and during your grow process.
The pH scale goes from 0-14 a score 7 in this range means that the pH level is neutral. Anything below 7 indicates an acidic compound and anything about 7 indicates an alkaline compound. Your hydroponic should have a neutral status or a score of 7 as often as possible. Examples of acids include nitric acid or phosphoric acid which when added to water have a "violent" reaction in which the compound breaks apart or ionizes. When referring to the strength of an acid this is in regard to the amount of ionization they go through.
In North America most water supplies are alkaline in nature, this is a good thing since many plants prefer a more basic environment near their root structure. If a plant absorbs nitrate ions that are negatively charged the roots will shed the negatively charged hydroxyl ions in order to establish electrical balance. This will raise the pH level of the surrounding root environment. If positively charged ammonium ions are absorbed positively charged ions will be shed causing a rise in the acidity of the root environment. Knowing how your plant cleanses itself with regard to its acidic environment is key when operating your hydroponic system.
As you consider your pH correction methods bear in mind that the pH level of the water is not the only factor to consider. The buffering capacity of your plant or its ability to resist pH changes need to be observed thoroughly when setting up your hydroponic system. Bear in mind that often many fertilizer components are acidic in nature and others are alkaline. When attempting to achieve the proper pH balance with fertilizer alone make sure to use water with as little bicarbonate as possible. Another thing to keep in mind while maintaining your hydroponic system is that when phosphorous levels rise they can cause the presence of magnesium and calcium within your water.
There are many different ways to test for pH levels in your hydroponic systems , among the most affordable and easiest ways to check you pH level are "pH strips", they are reactive strips that you soak in your water to reveal the current pH level. The strip will have a chemical reaction with the water and display where your hydroponic system's pH level is on a scale of 0-14. Do not underestimate the importance of maintaining proper pH balance within your hydroponic system, it is absolutely vital to the growth rate and overall health of your plants.