Please keep an open mind. There are a LOT of people out there that have a preconceived idea about the use of carbon in planted aquariums. Some of it is valid and a lot of it is not.
Topic:
Why using the proper carbon every so often to perform an aquarium water column reset is a good thing.
Background:
Not all carbon is the same. The process of making carbon and the materials used will dictate the best use of that carbon.
Some of it is designed for air purification. Others are specifically for water purification. The pore size and structure has a lot to do with what carbon will remove and won't remove.
Some of it is cheap and widely available, unfortunately, it's not the best to use in a planted aquarium. Most of the aquarium carbon products are cheap bituminous and it's not what we want to use.
The Argument:
The is no need to run carbon continuously in a planted aquarium. Depending on the type used, it may have an impact on fertilizer as some of it (that bound with organic binders) may be removed. That is counter-productive and the costs thus outweigh any benefits.
However, IMO it is beneficial to use the right carbon on occasion. By this I mean letting it run for 24 hours in your aquarium in a way that most of your water will run through it.
The benefits are:
- Removal of tannins and other impurities from your water that significantly reduce light penetration. We all know that carbon can make your water crystal clear. There have also been studies by Bulk Reef Supply showing how much light is lost to colored water.
- Removal of organics and volatile organic chemicals that are no bueno for anyone. I know we all think that our 50% water changes keeps the organics (and, hence, algae) away but do the math. Organic accumulation will creep up until you have more than you want because you are only remove half with every water change. By using the carbon every 3 - 6 months, you are removing 100% of organics from the water column and reseting the starting point.
- Removal of nutrients before they become a problem. As we've discussed in another thread on nutrient accumulation, there is an upward trend in the amount of nutrients in our water columns. This may have a detrimental effect in the long-term.
Like with our health, prevention is worth a pound of cure. This is the main reason why adding the occasional carbon protocol is beneficial. You are proactively removing some things that may create a problem down the road.
It's the same reason we do a water change even though nothing seems off. It's because we know that if we don't, thinks will go off the rails.
2. I do the occasional big water change. I'm already dealing with these problems.
While this is good, dropping in a bag or two of carbon will make this even better with VERY little hassle. The two are not mutually exclusive but supplement each other to achieve a better result.
Whatever the water change left behind will be cleaned up by the carbon.
3. I've heard that carbon removes fertilizer from the water. Why would I want that?
It does remove some of the nutrients but that's exactly the point. We want to clean out nutrient accumulation and the start with a lower nutrient point.
You will add back fertilizer as soon as you remove the carbon. After the 24 hour protocol.
4. My water is crystal clear. I don't have wood in the tank.
I'm happy for your maintenance skills but I would venture to guess that your water is not crystal clear. It's hard to tell in an aquarium. Just look at the BRS Investigates on carbon for crystal clear tank water.
5. I have carbon and will use that.
Great that I've convinced you to give it a try. However, don't just use any carbon. They are not all the same.
Get yourself either a specialty carbon like BRS' ROX Carbon or a coconut shell carbon. Both have a mix of micropores and macropores that will properly clean your water. Make sure to get the small pellet size so that it maximizes water purification.
Moreover, make sure to use it in a way that forces your water through it. Hanging it in your aquarium won't do. Either add it to your canister filter or pre-filter. Or, get your DIY mojo on and make yourself a simple canister and pump and hang it on your aquarium for 24 hours every 3-6 months. Ideally, combine it with a large water change and vacuuming.
I promise you that you won't be disappointed.
Anyone do this? I'd welcome any discussion of opposing point of view here.