Their are many methods of adding oxidants to the water which assists in changing the ferrous iron to ferric (clear water to a precipitate ie:rust). Oxygen can work but sometimes the effectiveness is marginal. It also adds a lot of air to the house water which gets annoying. We sell a lot of air injection systems, all have the common problem of airy water. H2o2 is more effective but also uses a consumable. It only makes the water in the house a tiny bit airy if it is overdosed. Chlorine is effective but obviously it must be very carefully controlled as high levels of chlorine can be very problematic. Ozone, pot perm, and many other methods are used all with their varying pros/cons. In general, if your budget allows a little extra treatment will usually prove highly effective compared to trying to save some money up front. Many people use h2o2 regeneration systems similar to the old pot perm systems. These have proven to be very effective as cost slightly more than the Air Injection system designs. Iron reduction is highly complex and different treatment methods work under different conditions. It is not like softening which is fairly universal in its application and expectations. Specialized medias can work without an oxidant like manganese dioxide which is used in Katalox Light, Birm, Greensand, Filox, Pyrolox and almost every other iron reduction media. Katalox light has become the primary media since it has a high percentage of manganese dioxide ore while still maintaining reasonable backwash rates. Its primary complaint is its over-stated abilities and the raise in pH that often accompanies the installation of this media. DO, ORP, pH, and much more need to be considered when using KL or any other iron reduction media. The ability to add an oxidant later if needed should be considered when installing any iron reduction system.
The 2510SXT is commonly used as an AIO valve and has decent capabilities. I would recommend it over the 5600SXT.