We receive a lot of questions related to the preparation and application of botanicals in aquaria, and we're happy to see them! It shows that we have an engaged, growing global audience, and we couldn't be more pleased about that!
One of the more common questions we receive is "Do I need to boil leaves before using them?"
I realize we've covered this many times before, but it bares repeating.
Here's a rundown of my very latest personal practices with leaves. I use one of two techniques:
1) I "steep" them for a bit in a container very hot, or boiling water. "A little bit" meaning say, ten minutes. Then, I give them a little rinse in room temperature fresh water, and use them in my aquariums.
2) I rinse them and gently rub them between my fingers to loosen up any dirt, mold, or surface debris that might be present, and then I place them in a container of room temperature water overnight, before using them in my tanks.
On a very rare occasion, I might simply rinse a leaf or two and toss them directly into my aquariums...but very rarely.
The idea behind steeping and soaking is to help soften the leaves a bit so that they are saturated, and to release any dirt or undesired contaminants from the outer layers of the leaves, without steeping gall of the desired humic substances and tannins out of the leaves entirely. Thats why I don't boil them or steep them for hours on end in boiling water. Don't worry, even with my recommended preparation process, they will still release plenty of these desired substances over time!
Although I have a great deal of confidence in my suppliers, and that they are sending quality, pollution and pesticide-free materials, you simply can never be too careful . Part of the "personal responsibility" of aquarium keeping, in my opinion, is taking the time to prepare these, and all botanicals before use. Skipping this process makes no sense to me.
The other question we receive a lot is in regards to how long leaves last, and what we do with them when they start to break down. The answer? Well, it depends!
First off, some leaves simply don't last as long as others. Which ones are least and most durable? Based on my years of experience in this area, I'd say it shakes out like this. From least durable to most durable:
Of course, your "mileage" may vary, and multiple factors come into play, such as the water chemistry, amount of current, types of fishes you maintain, your husbandry practices, etc.- but this is a good general guide.
Some leaves, in particular, Magnolia and Jackfruit, have a cuticle layer which keeps them "solid" for longer periods of time when submerged. It also means that they tend to recruit more biofilms and surface algae on occasion. This is either something that you find problematic ('because you don't like the look) or not (because you understand that this stuff happens in nature, is harmless, and is transitory).
If you don't mind it- just give an occasional scrape or rub the leaves now and again to remove this stuff with a siphon if t is too much for your aesthetic sensibilities. If you just despise it- go ahead and aggressively remove it in the same manner a couple of times a week, or as needed to keep it the way you like it.
In some cases, I know hobbyists who simply toss leaves at the first sign of biofilms...I personaly find that kind of wasteful, as the leaf itself, and the benefits it imparts into the water (humic substances and taninns) are still present. To each his own, I suppose.
This transitions us to the final question we receive most commonly on leaves: When do you remove them?
Well, again, it boils down ( hah!) to personal preference. I like to see them break down to almost nothing. However, I realize a lot of people don't like the look of decomposing botanical material in their aquariums, so you could remove them as they start to break apart. I've found no harm in leaving them in until almost completely decomposed, and only siphoning out debris that blow around the tank.
A good benefit of replacing them regularly is that you get a nice aesthetic "boost" by adding colorful new leaves regularly. And, removing and replacing the leaves regularly is very analagous to what's occurring in natural waters: As leaves break down they're either decomposed completely, or redistributed by currents. All the while, new leaves are falling into the waters from overhanging trees. It's an ongoing process, one that we can mimc easily in the confines of the closed system.
The other benefit of regular leaf replacement is that you maintain a certain degree of environmental consistency- a continuous "tint" to the water, more stable pH and (we think likely) levels of desired humic substances and tannin as well. Environmental consistency is so important, and relatively easy to maintain in a botanical system. Simply by doing the same things over and over, you're creating a certain "baseline" operating level for your tank, and providing its inhabitants with a more stable environment, requiring less constant adaptations to changes.
In the end, the use of leaves in an aquarium is not an exact science, and a good deal of the practices that we recommend are based on what has worked for us...and this may or may not work for you perfectly...that's the "art" part of the hobby of aquarium keeping..and that's the part that makes this so fun and exciting. Everyone's input and experience is important as we develop some "best practices" for botanical style systems.
In a future piece, we'll revisit the preparation and use of botanicals, with some good input from our growing global user base!
Until next time...keep refining, studying, and sharing. Stay Excited. Stay on the cutting edge. Stay open minded.
And Stay Wet!