If you've started working with aquatic botanicals over the past few months, you've probably gained an awareness that, although these are unique and aesthetically beautiful aquariums, like any other methodology, they are not "set and forget" systems. Because of the very nature of aquatic botanicals and how they interact with their environment, you need to regularly evaluate, scrub or even replace them as needed. You'll need to understand the progression of things that happen as your tank establishes itself. And, perhaps most important, you'll need to make some mental "adjustments" to accept and appreciate this different aesthetic.
We've talked on numerous occasions about the various "stages" through which a "New Botanical" aquarium progresses as it matures and settles in, which includes recruitment of biofilm, algae, and physical "softening" and eventual breakdown of the botanicals themselves. We understand that the materials will interact the aquatic environment directly, imparting tannins, humic acids, and other organics into the water. We like to call aquatic botanicals "dynamic" materials, as they are hardly "static" or "inert" in nature!
All of this adds up to a system that requires observation and management...Which, really, is no different, no more challenging, and probably even less mentally taxing than say, a "high tech" planted system or a specialized breeding setup for fishes like Discus or Angelfish. Like any system, the "New Botanical"-style aquarium requires some specific observation and maintenance practices in order to keep it performing at an optimum level for its inhabitants.
Startup-first 3 weeks: Observe botanicals to make sure that they are remaining "negatively buoyant" (i.e.; waterlogged!). Remove any which appear to be floating or present a putrid, "rotten egg-like" smell. Depending on your water chemistry, density of botanicals, and the filtration media employed, you'll start to see the "tint" usually after a few days, reaching it's maximum after about 3 weeks. Perform regular water changes and other maintenance like you would on any other aquarium during this time.
One month- two months: This is when you'll likely see some biofilms and algal growth on the botanicals. At this phase, you have several options. You can physically scrub the biofilms off of the botanicals as needed, or employ "biological controls" (such as ornamental shrimp, snails, or even Otocinculus catfish) to help with this process. Although they are efficient, you shouldn't expect the animals to get everything. You can assist with the removal of any offensive materials or...wait it out.
Two months-four months: By this time, your aquarium has no doubt settled into a comfortable, more stable situation, and you've come to appreciate the more natural appearance of your system. Some of the softer, more "transient" botanicals, such as leaves, have broken down significantly at this point, and no doubt need replacement. You employ regular maintenance practices, such as water changes, filter cleaning/media replacement, etc., and monitor water chemistry parameters like you would in any other tank. By this time, you'll come to recognize what is "normal" for your system, and any deviations from the norm will become more obvious to you. You can "top off" your system with some newly-prepared botanicals as you see fit.
Depending upon your goals, needs, and preferences, you can "condition" your replacement water for water changes by soaking some prepared Catappa leaves in the storage containers for several days prior to use. This creates a certain degree of stability, and of course, adds that "tint" to the water.
Evaluate periodically and decide if you want to exchange or simply add some new botanicals to your system. There is no exact "science" to this; like with so many things we do in aquariums, it will require you to "go with your gut" and make decisions based upon what your goals are, and what by now you consider "normal" for your system.
Obviously, this is not a comprehensive treatise on the management of a "New Botanical" style system. It was meant to serve as a rough guide as to what typically happens during the early life of such an aquarium. Your experience may vary slightly, but these observations were made based upon my own experiences and others who work with these types of aquariums. It's intended to serve as a "cue card" for you to understand the various phases of your aquarium, and what may be expected. Depending upon many factors, such as your base water chemistry, maintenance practices, filtration, etc., the timeline may be longer or shorter, but the "markers" are typically the same.
In the end, one conclusion you can draw from this brief review is that these types of aquariums- although not for everyone- are by no means difficult to create or maintain; and in fact, once established and stable, may prove to be some of the more simple systems you've worked with!
Probably the biggest adjustments you need to make are mental. You need to accept that this type of tank will look fundamentally different than other types of systems you've maintained. Obviously, the tint of the water is the most obvious. This can be managed, to a certain degree, by employing activated carbon. Purigen, or other chemical filtration to remove some or all of the "tint" as desired.
Also, you'll have to get used to a certain amount of material breaking down in your tank. It's natural, and part of the aesthetic. Accepting the fact that you'll see biofilms and even some algae in your system is something that many aquarists have a difficult time with. This is not an excuse to develop or accept lax maintenance practices. It's simply a "call to awareness" that there is probably nothing wrong with your system when you see this stuff. It's quite contrary to the way we've been "acculturated" to evaluate the aesthetics of a typical aquarium. Observe underwater videos and photos of environments such as the Amazonian region, etc. and you'll see that your tank is a much closer aesthetic approximation of nature than almost any other system you've worked with before! And, to your comfort, you'll find that these systems are as "chemically clean" as any other if you follow regular maintenance and common sense.
The realization that it's perfectly natural and entirely consistent with the nature of these environments to have some of this stuff present is little comfort to you if you just can't handle looking at a field of "yuck" on your botanicals. I can't stress enough the need to make that "mental shift." As we discussed, management of this stuff is entirely up to you and what you can tolerate. Generally, the biofilms and algae are self-limiting, ultimately disappearing over time as the compounds that fuel them diminish or attain levels that are not sufficient for their growth, or as a result of animals consuming them- or a combination of both.
The deterioration of "transient" materials like leaves and softer pods, etc. is simply part of the natural dynamic, and will continue as long as you choose to employ these materials in your aquascape. If you observe carefully, you may note spawning and other "grazing" behaviors in your fishes, and note that they are spending significant time foraging though the broken-down matter, much like in nature.
Ultimately, the decision to create a "New Botanical-style aquarium is as much a philosophical one as it is a practical one. To accept nature, rather than to fight it, is a bit at odds with the mindset many of us have with regards to aquarium keeping. As you begin to understand and evaluate your own aquarium, you'll gain a greater appreciation for the wonders of nature and the processes that have occurred for eons.
Stay open-minded. Stay creative. Stay diligent. Stay adventurous.
And stay wet.