If algae is simply a result of decaying organic material in the tank then why would any new setup suffer from algae?
Fresh substrate / filter media / new healthy plants - but algae (including but not limited to diatoms and BGA) can develop and persist. Even as plants have acclimated and are thriving in a new setup, algae can pop up almost out of nowhere.
Interesting points. As others stated, algae does not have a single point of origin. There is a multifactorial equation behind the existence of algae in an aquarium. Organic substances are one factor that may have a higher impact coefficient.
From my experience, problems with algae start to appear at around 2 weeks in the life of the aquarium…. Maybe the bacterial population becomes established at that point and enough organics accumulate. In this new environment there is also a fast succession of first (bacterial) colonizers, which grow and die (release organics) very fast. In the following months these bacteria are replaced by more stable populations.
It is also the case that some algae are observed after fish are added to a setup, sudden increase in organics. For example, if I induce increase in organics ( eg plant trim, plant damage) without cleanup or wc , bba bloom is sure to follow (bba was already present in small amount)
To complicate things further, as your righty point out, there are many different algae, some do indeed appear faster than 2 weeks under certain conditions. BGA profits from its ability to grow in NO3/NH3 poor waters ( typical for some new tanks). Diatoms are also observed in nutrient poor , high silica waters. Green water, another starting algae, seems to occur in high NH4, using all nutrients and then crashing. As you see, there are some factors that seem to tip the balance towards one algae type or another. Organics may be one of the factors for BBA, hair , GDA….
During this time and in to the future we need to switch from test kits to conductivity readings. This is easier, cheaper, faster and more accurate to overall living condition. Everything in an aquarium, alive or not, has some relationship to conductivity. (https://sites.google.com/site/aquati...home/tds-meter
The way it is done is to maintain consistent levels of pollutants, like fertilizers, substrate leaks, fish waste, decoration leaks and other with water changes... Plants and fish love consistency.
For example, when your tap is 300 µS, one PPS-Pro daily fertilizer dose is 6µS. This one dose is 1 ppm of NO3. So to limit the NO3 to 15 ppm we need to make sure the conductivity reading is kept under (6 x 15) + 300 = 390 µS. This is so easy.
And, no need to use GH Booster. It is not needed with tap.
I like the thinking process behind PPS-Pro and for large aquariums or areas with water restrictions this is a good method.
However, not so easy nor so simple. It is made seem simple by ignoring/misstating certain facts. Some organic molecules have 0 impact on conductivity. Conductivity is a good measure when working with electrolytes.
In addition, rock and substrate interactions can affect the conductivity of the water. To use your example, rock leaks Ca2+ and the conductivity in now raised above 410 µS. Does this mean we have more than 15ppm NO3? It actually tells us nothing about the conc. of NO3. Say we have a nice Montmorillonite substrate under basic conditions and a (real) NO3 of 40ppm. Ca2+ decreases, conductivity decreases down to 300. Oh, it must mean all our PPS-Pro dose was used. Conductivity measurement is great but it never ever replaces the specific test, no matter the calculations. Interactions between substrate, fish waste, rock and water are not consistent over time.
Even with daily dosing, you do not have consistency in the aquarium. I would rephrase it to plants and fish love the correct parameters. Fish that start spawning when conductivity abruptly drops are not actually very sad. What about plants that flower when P is increased ?
Dosing additional Mg and Ca is not needed with most taps, UNLESS you have very soft water or your GH is made out of Ca only or you have a high performance water softener.
So not so simple. PPS-Pro is a good starting point for running suitable nutrients without the big weekly wc, it is just more tricky to get and keep right than EI.
c) By calculation I have found out that for producing 450 grams of fresh weight the plants consumed 642 mg NO3, 58 mg PO4, and 262 mg K in 100 days. Converted to 60L tank volume, this means that the actual uptake rate of these plants was about 12 ppm NO3, 1.1 ppm PO4, and 5.0 ppm K per week.
So we should differenciate between these two things: external concentration of nutrients vs. uptake rate (and also between 'minimum external concentration of nutrients needed for maximum growth rate' vs. 'minimum uptake rate needed for maximum growth rate' vs. 'actual uptake rate').
Bravo @Marcel G
. A very good explanation of some complicated concepts. I would like to humbly add some points.
The (amount of ) elements that are present in the plants at the time of the measurement may not be all that is required by a plant to function. Like any organism, plants use some molecules /elements available in the environment as carriers. They also secrete organic substances/biproducts. Thus the C or N requirements might be higher because the plants loose some of it via ex/secreted molecules. As others who documented these molecules stated, some of them are returned to plant nutrients other are lost to the aquatic plants. A close to home example (with a bit of a stretch) would be the % of O in the human body is not the ppm of O2 that we need in the air in order to survive.
Thus the dry tissue analysis, although widely used, only serves as a ball-park, not the exact amount, composition or proportions of elements that the plant prefers.
A second point I would like to make is that most plants have a nutrient storage already with them when we subject them to different nutrient regimes. For some trace elements these storages might last very long in some plants. If the growth rate is slowed enough the plant can even survive in RO water for some months (years ?). This further complicates things when we talk about minimum nutrient level.
Food for though. Cheers.