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For a planted tank, I have written an article (on another forums) regarding some of the things you have to consider. I will simply copy and paste it here.

Edit: Comments/criticisms/replies are most welcome; I've noticed this thread has 30+ views and not one response from anyone else!

So you decided you wanted to start a planted tank, after seeing a beautiful aquascape in the AGA contests, or perhaps in one of Takashi Amano’s Nature World Aquarium books. Hopefully the guide I’m writing here will serve as a primer to jumpstart you into the world of planted aquaria.

Before starting a planted tank, you first must ask yourself: How much work (and subsequently time and money) do I want to invest into a planted tank? Beginners sometimes forget that many tanks that they see in the AGA contests or Takashi Amano's books are high maintenance tanks (i.e. require weekly pruning).

In essence, planted aquaria can take one of two forms: those that are high light tanks, and those that are low light tanks. Regardless of the type of lighting, algae can become a problem in both types of tanks if proper care and maintenance are not observed. Another question that must be asked at this point is: Do I want a low light (and hence lower maintenance (not maintenance free!)) tank, or a higher light (and thus higher maintenance) tank?

In general, there are 3 factors that are required for plant growth:

1) Light
2) Nutrients
3) Carbon dioxide

One can imagine these 3 factors like a triangle; a deficit in one or more of any of these 3 factors will result in an imbalance, allowing algae to take advantage of the situation and begin to flourish and grow.

· Administrator
12,230 Posts

Lighting is an important factor in a planted aquarium. It can be analogized as follows: light is like the accelerator of a car. The more light you have, the faster you are pushing down the accelerator. The less light you have, the less you are pushing down the accelerator. When you are driving faster, you must maintain your car more often, i.e. oil changes, checking your tires, and so forth.

Similarly, in higher lighting conditions, you will be "driving" your plants faster, and they will require more maintenance (i.e. carbon dioxide, nutrients, etc).

A guideline that can be used when describing lighting is the "Watt per gallon" (WPG) guideline. This is not a rule per se, but only a guideline (for reasons that will be explained below).

Lighting can be divided into 3 general categories:

1) Low lighting (~ 1 - 1.5 WPG)
2) Medium lighting (2 WPG)
3) High lighting (3+ WPG)

Correspondingly, plants can also be divided into these 3 categories, with "low light" plants being able to tolerate low lighting conditions, and "high light" plants requiring higher lighting conditions. This does not mean that "low light" plants cannot grow in higher lighting, however.

To explain why the WPG is only a guideline, one must consider the origins of it. WPG was originally designed for T12 fluorescent bulbs (i.e. bulbs that are 1.5 inches in diameter, the number after the T indicates the diameter in eighths of an inch). However, with the advent of various types of bulbs, i.e. T8, T5, power compact (PC) lighting, this guideline has become less accurate. In addition, this guideline cannot be applied in very small (10 gallons or less) or very large (maybe 55 gallons or more (ballpark figure)).

For instance, in my 2.5 gallon aquarium, I have two 13W compact fluorescents. This gives a total of 26 watts, corresponding to just over 10 WPG. This might seem suicidal at first (remember, the amount of light drives the amount of plant growth), however, because the WPG guideline is not accurate at small tanks, it turns out my 2.5g nano may fall under the "high light" conditions only (as opposed to "suicidally high light"). If I were to follow the WPG guideline strictly, and have 3 WPG over my 2.5g nano (i.e. 7.5 watts of light), then the tank would be poorly lit, and could only fall under a "low light" setup.

Not only is the amount of lighting critical to a planted tank, but the type of lighting is also important. As mentioned, there are several types of lighting available to the aquarist today (T12, T8, T5, PC, etc). Such bulbs can sometimes be confusing the novice planted aquarist. As a general rule, T8 and T5 are newer and more efficient than the older T12 bulbs. There are two camps of thought, one which prefers PC lighting while the other prefers T5 lighting, but to argue the points of these two types would be beyond the scope of this article.

One must remember that in general, fluorescent bulbs are all subject to a phenomenon called "restrike". In restrike, light that is emitted from the bulb will "restrike" the bulb, reducing the output of effective light. In general, straight fluorescent tubes are less prone to restrike than (say) the spiral power compact bulbs that can be purchased.

For some, the "colour temperature" of the bulb will also be a consideration. Plants in general are not too picky regarding the colour temperature, and some may argue that this point is not necessary, however, I have decided to briefly touch upon this.

In "normal" daylight, the sun is 5500 Kelvin (the unit of measure for colour temperature). Higher colour temperatures will appear bluer, while lower colour temperatures will appear redder. Here are some typical colour temperatures that can be found:

2700K "warm white"
3500K "cool white"
6500K "daylight"

Do keep in mind that light is but one important factor in keeping a successful planted aquarium

· Administrator
12,230 Posts

Another important aspect of the planted aquarium is nutrients.

Plants require macronutrients NPK (nitrogen in the form of nitrates; phosphorus in the form of phosphates; and potassium) amongst other elements. Micronutrients (such as iron, copper, manganese, boron, molybdenum, etc) are also required by plants. It is a common misconception that the addition of phosphates leads to algae; this is not true. Phosphates are an important part of plant nutrition and is required by plants to grow successfully. As long as there is a balance between nutrient levels, lighting and carbon dioxide, you can have a successful planted aquarium.

There are several ways to provide these nutrients to plants. In a mixed aquarium (i.e. with fish and plants) with few plants, the wastes from fish can sometimes meet the demands of the plants. However, in heavily planted tanks, the demands of the plants can rarely be met by fish wastes alone. As such, supplementation must occur.

Supplementation can be provided via commercially available products (i.e. Seachem makes such a line of products). Alternatively, one can go for the "chemical" approach. Using this approach, various chemicals can be added to the tank in order to provide the nutrients that plants require. For example:

Potassium nitrate (KNO3) provides potassium and nitrates
Potassium dihydrogen phosphate (KH2PO4) provides potassium and phosphates
Potassium sulfate (K2SO4) provides potassium and sulfur (in the form of sulfates)
Magnesium sulfate (MgSO4) provides magnesium and sulfur (in the form of sulfates)
Trace mix provides various trace elements (Iron, Copper, Molybdenum, etc) that are required

In general, the levels that are desired in a planted aquaria are as follows:

Nitrates: ~10 ppm
Phosphates :~ 1-2 ppm
Potassium: ~20 ppm
Iron: ~1 ppm

There are several different regimes that are available today that can be followed in order to dose appropriately. As I did not write these articles, I will simply link to them here.

The estimative index (EI) method of dosing was created by Tom Barr and can be found here:

The PPS-Pro system was developed by Edward and can be found here:

· Administrator
12,230 Posts
Carbon Dioxide

The last major factor in a planted aquarium is carbon dioxide (CO2). In a planted aquarium, typically 30 ppm of CO2 are desirable (see below for measuring CO2).

Carbon is an important element for plants; they require this element in order to grow and propagate (i.e. all organisms on Earth are carbon based!).

Terrestrial plants do not require carbon dioxide, as they are able to meet their carbon needs from the atmospheric air. However in the aquatic environment, levels of CO2 are typically 4 ppm (parts per million), and are insufficient for plant growth in the long run. Recall that in higher light tanks, plants are being driven harder, and as such, carbon dioxide (as well as nutrients, see above) become an essential part of the planted aquarium "triangle".

Sources of carbon can be introduced into the planted tank in 2 ways:

1) Seachem Flourish Excel
Using this method, a commercially available chemical (polycycloglutaracetal) is added to the tank as an alternative source of carbon. Note that this is not carbon dioxide, and is only an alternative to carbon dioxide. It is not as effective as carbon dioxide itself, but can work. This method can be used in smaller tanks, but quickly becomes cost prohibitive in larger tanks.

2) Directly injecting CO2
Directly injecting CO2 is the best method of introducing a carbon source into the planted aquarium. One can accomplish this in one of two ways, each has its advantages and disadvantages.

a) DIY (do it yourself) CO2
Using this method, sugar and yeast are mixed into a container. As the yeast begins to feed on the sugar, carbon dioxide is produced as a byproduct of fermentation. This carbon dioxide can be fed into the water, and provides a source of carbon for plants.

- low initial cost
- effective for smaller tanks
- relatively easy to setup (i.e. not much technical expertise required)

- expensive in the long run
- becomes difficult to maintain in tanks larger than 30 gallons (i.e. more than one bottle of DIY CO2 may be required)
- inconsistent production of CO2

An excellent resource for DIY CO2 can be found here:

b) Pressurized CO2
The second method of introducing carbon dioxide into your tank, this method is preferred for larger tanks where DIY CO2 may not be suitable/too much of a hassle. In this method, a pressurized tank containing CO2 is injected into the aquarium, much like in DIY CO2. The following advantages and disadvantages can be said for pressurized CO2:

- Consistent CO2 flow
- Cheaper in the long run
- Requires less maintenance than DIY CO2

- high initial setup cost (i.e. a tank, regulator, needle valve can run upwards of $150; there are also some optional pieces of equipment such as a solenoid, bubble counter, etc)
- some technical expertise is required (i.e. knowledge of how a regulator works)

When introducing CO2 into the planted aquarium, it is also better to fully dissolve the CO2 than to let it bubble off. Dissolving the CO2 ensures that it is available to plants, and not simply out gassed into the atmosphere. Several methods of effectively getting CO2 into the water column exist.

1) Bell Diffuser: A passive method of CO2 diffusion, this relies on the assumption that CO2 will dissolve into the water column faster than the CO2 is produced (not likely). Not an effective method of introducing CO2 into the aquarium.
2) Feeding the CO2 tube into a filter intake: Slightly more efficient, this method allows the CO2 bubbles to be fed into the intake of a filter, allowing the bubbles to be chopped up by the filter impeller. Be warned that this method is said to shorten the lifespan of the filter impeller.
3) Commercially available "bubble ladders": Hagen makes a product that is known as "bubble ladder". This product allows CO2 bubbles to travel a long a track, allowing the CO2 more time to dissolve into the water column. The ladder is quite large and bulky (in my opinion), and some people may find it aesthetically unpleasing.
4) Ceramic disc diffuser: Typically a glass diffuser that contains a ceramic disc with miniature pores. These diffusers were first made by ADA (Aqua Design Amano). Such diffusers rely on the small pores on the ceramic disc to adequately create mini-CO2 bubbles, vastly increasing the rate of CO2 dissolution in water.
5) Inline CO2 reactor: Most arguably the best method of CO2 dissolution, the inline CO2 reactor is inline with a (canister) filter output. Using this method, the CO2 is very effectively dissolved.

· Administrator
12,230 Posts
Measuring CO2 Levels

So you have started to inject CO2 into your planted tank, but you are unsure whether you have too much/too little.

If you are injecting too little CO2, there may be the possibility that plants are starved for carbon. If the "triangle" is unbalanced, recall that algae can take over.

Conversely, if you are injecting too much carbon dioxide, it is possible to suffocate your fish/invertebrates. The goal is to find a happy medium between these two extremes (around 30 ppm of CO2 is desirable).

Measuring CO2 can be accomplished in several manners.

1) Electronic CO2 meter
A very expensive piece of equipment, not many aquarists have the budget necessary for one of these pieces of high tech gadgetry.

2) Measuring pH/kH
Measuring pH and kH is a method of determining the amount of CO2 in your aquarium. This method relies on the fact that there exists a relationship between pH, kH and the amount of CO2 that can be dissolved. However, one must keep in mind that this method is only an estimate; there may be other buffers in the water that may skew results from this method.

An excellent article by Chuck Gadd as well as an in-browser CO2 calculator and CO2 reference chart can be found here:

3) Drop checker
Most likely the newest addition to measuring CO2 levels, a drop checker consists of an airspace between the liquid inside the drop checker and the water in the aquarium. Carbon dioxide readily diffuses outwards from water into the air; as such, the carbon dioxide in the aquarium will readily diffuse into the airspace in the drop checker. The liquid inside the drop checker contains a solution of known kH (i.e. 4 or 5 dkH) with an indicator (bromothymol blue (BTB)) which serves as a good indicator of CO2 dissolution. The CO2 that is in the airspace of the drop checker will readily diffuse into the drop checker solution, changing the colour of the BTB indicator.

A guide to making your own DIY CO2 drop checker written by me (shameless plug here!) has been copied below for your reference.

After some reading on various forums, and since I started DIY CO2 in my 2.5 g nano, I decided to build a DIY CO2 drop checker on the whim (hey, it's reading week, I get a break from university midterms, I deserve to spend some time with my aquariums! :p)

Anyways, here's the equipment you will need, or rather, the stuff that I had lying around my house that I used:

1 Glass container with screw on lid
1 Silicon glue applicator/similar type glue applicator
1 Rubber O ring that is about the same size as the screw on lid
Power drill with appropriate drill bits
1 Suction cup
1 Zip tie


Glass container with lid

Glue applicator with the tip cut off so it will fit into the glass container

O Ring

As mentioned, you'll have to cut the plastic applicator so that it fits within your container first. Next, you'll want to drill a hole in the cap.

Finally, you can put the O-ring onto the applicator, put the applicator in, and screw on the lid.

Next, I needed some way to mount the whole thing in my nano, so I used a spare suction cup and a plastic zip tie.

You'll notice the zip tie just goes through the suction cup (i.e. I just put a hole through the nipple of the suction cup).

After the mechanical work was done, I had to start the chemistry part (I love chemistry!)

Items you'll need to make a 4 dkH reference solution for the drop checker:

1 Graduated Cylinder
1 Scale that can measure to at least 0.1 gram accuracy
1 Box of Baking Soda
1 Bottle of Distilled water


Scale that I bought off a site, it was $11 (free shipping)

Baking soda (sodium bicarbonate), you can pick this up at your grocery store.

Distilled water, again, grocery store.

First, since a 4 dkH reference solution is needed, I made the necessary calculations and prepared a 40 dkH solution before diluting it 10 fold to 4 dkH.

To make a 40 dkH solution, you need 1.2 grams of baking soda per 1 L of water. I made up a 2 L batch, so I needed 2.4 grams (the bigger the batch, the more accurate your final solution will become).

Then, taking 50 mL of the 40 dkH solution (measured with a graduated cylinder), I poured it into a bottle and filled the last 450 mL with distilled water (giving me a 1:10 dilution = 4 dkH solution).

After you make your 4 dkH solution, measure out 5 mL, and using a pH test kit (i.e. I used the API pH test kit, any test kit that uses bromothymol blue will be fine for this purpose), put in at least double the recommended number of drops (i.e. API recommends 6, I put in 8-9 drops). This makes the resulting solution darker, and easier to read.

Here's the liquid inside the drop checker.

Everything put together, just awaiting me to strap the drop checker to the suction cup.

The whole contraption has been placed into my nano, around 4:48 pm. At the time of writing this up (5:35 pm) the top portion of the liquid is already starting to turn green. :)

6:28 pm now, it's definitely green :)

· Administrator
12,230 Posts
Will having CO2/ferts expand your effective light range.
Think of light as a gas pedal of a car. The harder you press down on the gas pedal (the more light you have), the faster your car will go (the faster your plants will grow). However, the car will require more regular maintenance (your plants will require more maintenance, i.e. fertilizers, CO2, etc).

Even if you dose fertilizers and inject CO2, you will not be able to grow a high light demanding plant in low light conditions.

If there are no fish (there are a few snails) do I have to worry about CO2 levels or can I just throw a DIY system on there and not worry about oxygen levels.
There is a common misconception that injecting CO2 will force out oxygen. This is not the case. You can inject much CO2 while the oxygen levels remain fairly stable. The reason fish/invertebrates die is because the CO2 can bind to hemoglobin, causing gas exchange to not occur (even though the water could have high levels of oxygen).

If you do not have any living organisms in your aquarium, you could crank your CO2 up as high as you want.

Is there such a thing as over fertilizing. In a tank with or without fish ( I also have a 55 planted with fish, moderate light but no CO2) is it possible to overdose the fertilization to the point where it negatively effects plants (in a non fish tank) or fish in an populated tank.
In a tank with fish, the more fertilizers you add, the higher the total dissolved solids (TDS) becomes. This can become stressful for fish.

In a planted tank without fish, excessive levels of nutrients would just be a waste. There is really no need to continue dosing if the plants aren't going to use it up (i.e. if your car gasoline tank is full, you do not keep putting gasoline into the car).

Will regular dosing of ferts and presumably healthy plants ever be enough to get rid of the BBA or once I have it even if it isnt spreading it will not go away on its own. Will the addition of pressurized CO2 cause the algae to die off? And if I add CO2 should I discontinue Excel, but continue on with the other ferts?
BBA is a difficult algae to treat once it has taken ahold. The presence of healthy plants will definitely discourage its growth, but you will likely need to manually remove the BBA to remove it. Healthy plants will then keep it from coming back.

You can always spot treat with Excel (using a syringe) to blast the BBA.

If you add CO2, you can discontinue Excel, as they are redundant. However, as mentioned, you can use Excel to spot treat to eliminate BBA. Finally, you will need to continue to add fertilizers, however.

If I ran CO2 would I be a fool to continue running the airpump, at least when the light was on? Or if it is pressurized CO2 put through a reactor, will it not matter.
I would turn the air pump off during the day if you are injeccting CO2. If you want ease of mind, you can always put the air pump on a timer so that it comes on at night.

Regardless if you use a reactor or not to diffuse the CO2, agitation of the surface of the water (i.e. via the air bubbles) will cause the CO2 to diffuse more quickly into the atmosphere.

The air pump is a model for a 20 gallon tank, so it isnt pumping out huge amounts of air, but I had shut them off when I first started using Excel, and I guess I had a ph crash (if thats possible with Excel)
It is not to my knowledge that Excel can cause the pH to crash.

So I am nervous about the whole CO2 / lower oxygen level issue...
As I mentioned, the injection of CO2 does not displace oxygen. A drop checker (with a 4 dkH reference solution) will be a useful tool in order to determine whether you are over injecting your CO2, however.

· Administrator
12,230 Posts
In high light aquariums, CO2 becomes a necessity.

As you mentioned, there are some cases where CO2 injection is not required. For example, in a low light aquarium, as there is less growth overall from plants, there is less demand for CO2, and as such, it is not necessary.

However, even in low light aquariums, the injection of CO2 has its benefits.
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