Chemistry is one of the subjects that impacts highly applicable knowledge, especially if you're in the carpet cleaning industry. Understanding the chemical makeup - particularly the pH level - of a cleaning solution can really be the difference between having a discolored, variegated carpet and one that comes out looking rejuvenated. Below will be a guide on the pH levels for carpet cleaning to ensure that your carpet does not get damaged.

The pH level of a solution refers to the alkalinity or acidity of a water-based solution. It's measured on a spectrum ranging from 0 (most acidic) to 14 (most alkaline), with 7 being neutral. So, anything below 7 is acidic, and anything above is considered alkaline.

Note that even though the range are in one-point increments, in reality, each one-point increment represents a 10 time increase from the previous level. Therefore, the progression is more geometric than arithmetic.

The pH of the cleaning agent will usually depend on the acidity or alkalinity of the dirt. For acidic soil (most dirt), you'll need to use an alkaline carpet cleaning agent. While for alkaline, you'll need a more acidic cleaning solution that's between 2 to 5 pH.

The Institute of Inspection Cleaning and Restoration Certification recommends that carpets with relatively moderate traffic, like in residential homes, be cleaned with carpet solutions whose pH is between 8 and 10. Areas with heavy traffic, like in restaurants, can use cleaning solutions with higher alkalinity, from 12 upwards. In both cases, the professional cleaners will need to check that their solutions and methods don't void the carpet's warranty.

Carpets made from natural sources, like wool, should be cleaned with mostly neutral solutions, so their natural color and fiber texture is protected.

When to Use Acidic Cleaning Solutions

Most carpet cleaning requires alkaline cleaners, however, certain situations may warrant acidic cleaning agents. For example, if after a carpet is shampooed, the vacuum extractor used to remove soap residue doesn't effectively remove all traces of the detergent, the carpet will be alkaline - which can resoil it. Only an acidic solution will break down this alkalinity. Most professional carpet cleaners bypass this problem by using encapsulation - drying out oily soil, then vacuuming it out.

One obvious way to know what your carpet fiber is to ask the manufacturer, or the store you got it from. If you can't do that, you can take a piece of the carpet and burn it using a butane lighter in a small ashtray. Different fibers produce different flame colors and outcomes. Synthetic (or most) carpets will leave a hard plastic-like bead behind when burned, while wool will burn orange and smell like hair. Once you know what fiber you're dealing with, you can then choose the pH level to use.

As mentioned earlier, most carpet dirt is acidic (food, body fluids, etc.), and so require alkaline cleaning agents.

Other factors to bear in mind when deciding the pH levels for carpet cleaning agents include carpet age, dyes and colors used to treat it -- and of course, don't forget the manufacturer's instructions.