Fred Dulley said:
ceg4048 said:
require high maintenance effort due to higher levels of generated organic waste.
Hi Clive.
Can you give some examples of this organic waste?
Obviously water changes will help dilute this waste but does carbon in the filter help too?
Cheers.
Apologies for going off on a tangent.
Howdy Fred,
For starters, here are some examples of general tank organic waste. These are fairly obvious and not all are plant produced:
1. Fish poop.
2. Uneaten food.
3. Dead leaves
4. Dead bacteria
Here are the ones that people never think about:
4. Sugars and other Carbohydrates ejected by the plant.
5. Proteins and lipids ejected by the plant.
Everyone assumes that chemical movement in aquatic plants is unidirectional. That nutrients and water flow into the plant via roots and leaves, but this is only half the story. Plants strip the carbon from CO2 and produce sugar as a fundamental product. Although they use the sugar as their own food, retention is not 100%. These sugars leech across cell membranes into the water column and sediment. This is one way in which they feed the nitrifying bacteria who, many forget, also need carbon for structural building blocks. There is a symbiosis between plant and bacteria. The convert the otherwise inaccessible CO2 to sugar and oxygen and the bacteria use the sugar for fuel, they burn their fuel with oxygen and use the oxygen to detoxify the environment such as oxidizing NH4 to NO3. The "O" in NO3 is Oxygen. So the more Oxygen that is made available, the more NO3 that can be produced, which is then taken back up by the plants.
Plants also leech proteins and lipids which are broken down by the bacteria. The lipids show up as the thin oily film at the surface. In this way, other elements such as Phosoporous, Magnesium and so forth which are needed by the bacteria can be fed to them in an organic form which they can assimilate. So for example, a bacterium does not have access to the Magnesium in MgSO4 but that Mg taken up by the plant is then woven into some organic protein the plant then produces (and later ejects), which the bacterium can later break down and eat, in exactly the same way we access the vitamins and sugars from fruit.
At low levels of light, low dosing and low CO2 these products are ejected slowly (an of course at low concentration levels), but when the environment becomes eutrophic then the ejection rate rapidly increases. In large bodies of water, or in open natural systems the concentrations never become a problem, however, in closed systems such as we have, high rapid organic waste build up is not only fodder for algae as they break down, but they actually stifle plant growth as well, further injuring the system.
In a high tech tank, one of the best things you can do is a water change. The cleaner the tank, the better your plants will grow. This is why the water change is so important in EI. It's ironic that so many people are paranoid about nutrient build up with EI when the real problem is the very products of growth that EI generates as a direct result of the elevated nutrient levels.
Cheers,