Re: Low Energy, Water Changes, CO2, Algae, and Pseudoscience
sWozzAres said:
The problem is that anecdotal evidence is typically presented with assumptions and without knowing what these assumptions are it's difficult to assess it's validity. Science suffers the same problem but to less a degree.
Well, some use both methods, and rather than seeking cause, they seek to falsify what they can test.
This seems to work with a higher degree of certainty and within the hobby fairly well.
Searching for the cause itself...........may not.
Anyway Troi, the situation is this, you aren't convinced that fluctuating CO2 causes BBA because you change 30-50% of your water each week and don't have BBA. Well, if you take anyone that has BBA and trace the "causal chain" back to the big bang! you will probably discover that somewhere along the way, there is a change in CO2. This doesn't mean change in CO2 is THE cause, it just means that it's one of many events that lead to BBA. BBA comes from fluctuating CO2 but the reverse is not always true - fluctuating CO2 doesn't always cause BBA. Complex web of interaction in a complex dynamic system, all tanks are different. People look for THE one cause because they want to understand and the easiest way to understand is to simplify. Simplifying has limits. Some algae are easy to defeat, other's like BBA and GSA have multiple causes hidden amongst the complex web of cause and effect - probably due to their non trivial life cycles.
Anyway for what it's worth, I think that BBA is caused by multiple events - at least depletion of CO2 followed sometime later by it's return. Anecdotally, I've only ever had an outbreak when my CO2 runs out and I've not noticed for a couple of days. Perhaps depletion causes spore release which then germinate when CO2 returns. You don't get BBA because your CO2 never gets fully depleted. Depletion could happen in any corner of the tank which might be why people have minor BBA that never results in an outbreak. But hey, what do I know, I'm a casual user and I'm fully prepared to change my mind tomorrow - in the meantime, I will continue to keep the lights off when my CO2 runs out!
Good post there and well stated.
But back to falsification, you can vary the other complex variables like light, NO3, PO4, etc and falsify those as singular causes, or cook up any number of combinations you suspect. This could take awhile, but you can rule out many other species of algae and interactions along the way for each nutrient.
Then perhaps measuring O2, or filtration type etc, or current, or tap water differences between sites etc.
At least this way, you can rule singular causes and start looking at the more complex. If you cannot falsify something, then.......well.............we sort of tentatively accept and drag our knuckles on that one and sheepishly accept it till proven wrong.
We can also use over all plant growth concepts such as very high light = the highest demand for resources......CO2 and nutrients etc..........and apply those to the system to see results faster/more immediately/more strain, whereas they might appear slow and subtle in a low energy lower light/non CO2 approach.
Basically choosing the most susceptible, sensitive cases, much like when miners used the Canary in a cage for toxic fumes.
A combo of methods and observations(anecdotes) seem to work the best. We need to be able to corroborate theory/test etc........in the field (our aquariums). So we have to try it and see. Some things are not simple, sometimes we just over looked something really simple
Done this many times.