I had a customer call me after a cleaning where brown stains and coffee stains were treated saying they were still wet and now has a brown ring around them. What causes this brown ring with browning treatment and how do I keep them from coming back?
There are several types of browning treatment. It is helpful to know which one or at least which type you are using.
Some use acids. These are usually the cheapest browning treatments and not always effective.
Some use mild reducing bleaches, general sodium sulfite or sodium metabisulfite. These are powders. The strength can be adjusted by how much you use and the temperature of the water you use. Bridgepoint and Chemspec both make one of this type.
Some use stronger liquid reducers. They work well if used properly. They can be mis-used and either get no results or take out color that you did not want to remove. They are also more expensive.
Rings after using a browning treatment usually mean that you used too much liquid, got the carpet too wet and brought contamination up from the backing or cushion.
Try to correct by using an encapsulation product like Encapuguard (mix, spray on and brush in) or Encapuclean which can be applied with a bonnet or a towel by hand.
Knowing the type of browning treatment and the fiber involved and the equipment you have available to correct the problem would allow for a more specific answer. Do not over-wet.