The Watchwater product historically known as Katalox Light is now being called Katalyst Light by the manufacturer. In a conversation with Watchwater it was confirmed that the formulation has not been changed at all - this is a name only.
Katalox/Katalyst Light is a very popular media used in iron water filters and other water filtration units. It has three distinct advantages over competitive iron reduction filtration medias:
1. Katalox/Katalyst Can Remove More Than Iron
Iron is often found in water that contains two other destructive and annoying water contaminants: manganese and sulfur. Manganese is very similar, chemically, to iron, so most filtration medias that can manage iron will also manage manganese. However, sulfur is much more of a challenge. Competitive media types (like Birm) cannot remove sulfur and in fact is eventually destroyed by it. Katalox/Katalyst Light on the other hand is quite effective in reducing this stinky contaminant and is preferred for use in sulfur water filters for this very reason.
2. Katalox/Katalyst Can Operate At Lower pH
The ability for iron/manganese/sulfur filters to remove these contaminants is very tightly tied to the pH of the water being treated. The higher the pH, the more this favours the chemistry that takes the dissolved forms of these contaminants and converts them to their particulate form that can be mechanically filtered out of the water. Many iron/manganese/sulfur medias require a pH that is 7.5 or higher to effectively treat the water. Katalox/Katalyst Light is able to treat water with a pH of 6.8 or higher giving it the ability to operate in a much broader range of applications. With this being said, even for Katalox/Katalyst Light, the higher the pH the more effective it will be.
3. Katalox/Katalyst Can Be Properly Backwashed
The main mode of failure for the vast majority of iron/manganese/sulfur filters is that the residential plumbing system is incapable of properly backwashing the unit and it slowly (or sometimes quickly!) fills up with oxidized material. These systems can be difficult to properly backwash because the medias used in them are exceptionally dense and require a very high flow rate to backwash them.
Katalox/Katalyst Light solves this problem by wrapping the reactive surface of the media particles around a core of much lighter material. This makes the media much less dense and requiring a much lower flow rate to properly backwash. This makes systems that use Katalox/Katalyst Light much more easily deployed in residential environments where the plumbing and pumping systems may limit the flow that can be provided. The result is systems that work better and work much longer than competitive systems do.