If the problem is water discoloration due to runoff or organic decomposition, then the best solution is to first reduce the cause of the discoloration. If the runoff or organic decomposition can not be addressed, such as stopping the runnoff or cleaning up some of the organic decomposition, then you might be fighting an ongoing expensive battle to remove the water discoloration.
To understand more about Zeolite, then read
post#10 in thread "Ammonia question... reading from the strip." Zeolite functions due to a cation exchange system and nothing about zeolite implies having an "activated carbon ability" to absorb chemical discolorations out of water. I do not see the connection of "zeolite doing everything activated carbon and then some".
As with most these products, installation and volume used of these two products will determine its effectiveness. For installation, I like the
Childer's DIY water filter. These products work best when the water has thorough contact with the product's surface area. Placement is best if you can place the product so the water can squeeze through the product rather than water flowing over the product. Keep in mind that these products will need to be removed to either, in case of Zeolite, to recharge it or, in case of the carbon, to dispose of it.
For chlorine or chloramine treatment, I am a big fan of the water filters that Mmathis has shown above. The most common mistake are folk's auto-fill float or electronic valves sticking or forgetting to turn off the garden hose that is adding water to the pond. To be aware of the number of gallons you have used, then you can install a cheap water gallon counter hose attachment after or before the filter.
The cheapest route to neutralize chlorine and to neutralize the chlorine in chloramine is to use a product called Sodium Thiosulfate. To understand more how to use it, where to get it, etc, then read
post#17 in thread "adding water." This product is a basic chlorine neutralizer and does not do all of the
unnecessary "fancy features" of other dechlorinators.