shipment from aquaticplantdepot.com

[Roujin]

Awesome links. Man, the idea of no water changes. It boggles the mind, lol.

LOL! The laws of the universe don't typically apply to a planted tank.

[Complexity]

Quick question: is it possible to over-fertilize?

The short answer, as you have already received, is yes.

But there are a couple of additional questions to consider.

How often does the average person over-fertilize? Very, very rarely.

How likely is it that you will over-fertilize? Very, very unlikely.

How often does the average person under-fertilize? Very often!

I want to stress this because while it is possible to over fertilize, you would have to really overdo it to reach that level. Given that it is far more common for people to under-fertilize than to over-fertilize, I want to discourage the fear of using fertilizers. Of all the problems in keeping planted tanks that people run into -- including algae -- over-fertilizing is almost never the root cause. However, under-fertilizing generally is. So be more concerned with under-fertilizing than over-fertilizing.

There are 3 basic elements to plant growth (and I propose a 4th, as well, which I will explain in a second post). For now, let's get the basic 3 established.

1. CO2 -- plants require the carbon from CO2 to grow. Plants cannot produce a physical leaf without something physical to create the leaf. Carbon from CO2 is that physical element. Without carbon, plants do not have the basic building blocks in which to use for new plant material (such as a leaf, stem, or root).

2. Fertilizers -- without proper fertilization, plants cannot grow in a healthy manner. It is no different than all other living things, including humans. If any specific nutrient is missing, the plant's growth will be unhealthy. It might be stunted or it might grow in a poor manner (such as yellow leaves if there isn't enough iron).

3. Light -- now if there is anything to fear, this is it. The one, single element that causes the most difficulty with planted tanks is the lighting -- too much intensity, too little intensity, and too long a photoperiod. Too little light intensity and the plants cannot grow to their potential (and in some cases, cannot grow at all). Too much intensity and algae will grow. Too long a photoperiod will also cause algae.

Of these 3 elements, the one most people have difficulties with is the light. That is because the light has the greatest overall affect on plant and algae growth. In simple terms, the brighter the lighting, the faster everything will grow. This also means that if anything is out of balance, the faster the problems will manifest themselves (meaning algae). It's like everything's on speed. If all is going well, the plants will just grow super fast. If there's a problem, that problem will get out of hand super fast.

In general terms, it is best to keep the lighting low or medium until CO2 and a good fert program is in place. This will go a long way in keeping algae at bay, and if algae does break out, it will not take over the tank as quickly in a lower lighting setup which gives you more time to make adjustments to combat the algae.

But the question is about ferts, not lighting. So next I'll post my theory regarding plant mass and ferts.

[Complexity]

My theory of the 4th element, plant mass.

4. Plant Mass -- I came up with this concept after reading so many posts from people who ran into problems with tanks with low plant mass. Reducing the amount of fertilizer didn't seem to help the problem. Instead, increasing the number of plants did. I had also seen those with a lot of experience with planted tanks strongly recommend stuffing the tanks full of plants when starting out. So I tried to figure out why decreasing the amount of fertilizer did not help while increasing the number of plants did help? This is what I finally came up with. I don't know if it's true, but it seems to make sense. And it's the only thing I could come up with to explain why plant mass was more important in avoiding algae than reducing fertilizers.

I'm going to use numbers to express the concept; however, the numbers themselves are meaningless. You cannot have "1" or "10" fertilizers. It is the relationship between the numbers that's important as it is possible to dose 10 times more fertilizer.

Let's say we have a 10g tank. In this tank, we plant just 1 plant. Now we decide to fertilize that one plant. The plant needs 10 fertilizers to grow well.



PROBLEM 1:
If we use the fertilizer rates normally recommended for a 10g tank, we'd end up with a lot of extra fertilizer in the water. This will encourage algae to grow. The plant can only use so much fertilizer. All extra fertilizer just sits in the water.

1 plant
100 fertilizers put in the tank
Each plant gets 10 fertilizers <-- perfect!
90 fertilizers excess (for algae) <-- too much



The plant gets all the fertilizer it needs, but the tank is left with excess fertilizer which encourages algae growth. This clearly is not the way to go.



PROBLEM 2:.
It would seem reasonable, then, to reduce the amount of fertilizer put in the tank. If one plant only needs 10 fertilizers, then why not put just 10 fertilizers in the tank?

The problem is that the fertilizer is diluted throughout the entire tank. The plant only comes in contact with whatever fertilizer is in the water it physically touches (it can't grab the fertilizer from the water across the other side of the tank).

1 plant
10 fertilizers put in the tank
Each plant gets 1 fertilizer <-- too little
9 fertilizers excess (for algae) <-- too much



So now we have two problems. (1) We still have excess fertilizers in the water, albeit at a much weaker strength, and (2) now the plant is not getting all the fertilizer it needs. It needs 10, but is getting only 1. This isn't the solution.



SOLUTION:
So what happens if we add plants instead of decreasing the fertilizer?

10 plants
100 fertilizers put in the tank
Each plant gets 10 fertilizers <-- perfect!
0 fertilizers excess (for algae) <-- perfect!



Every plant gets all the fertilizer it needs for healthy growth AND there is no fertilizer left over to encourage algae growth. Now things are in balance.

So the answer is to not dose a weak amount of fertilizer, but to be sure you have enough plants in the tank. While it is possible to have a tank with just a few plants, it's a much harder tank to care for. Unfortunately, most people just starting out with planted tanks usually start out with just a few plants, and many times they start out with slow growing plants which complicates the problem even more. So most people start out with a much more difficult setup. Then they get algae, think they're using too much fertilizer, decrease the ferts, and then end up with poor plant grown in addition to the algae. It becomes a vicious cycle.

The easiest way to start out is with a ton of plants (especially some fast growers) and medium lighting. If you dose ferts, dose the full recommended amount. Get your CO2 up and running. As you gain experience, you'll be able to make adjustments to fit your tastes while still maintaining a healthy planted tank.

And if you (or anyone else reading this) wants to have a tank with bright lighting, then (1) stuff the tank full of plants, (2) get injected CO2 up and running, (3) dose dry ferts and then, (4) add bright lighting. It's much easier to get a "high-tech" tank up and running if the steps are taking in that order.

So, yeah, you can over-fertilize, but it's really not a big problem for most people, and it's rarely the cause of the algae outbreaks most people run into when setting up a planted tank.