plantbrain
Expert
- Joined
- 2 Aug 2007
- Messages
- 1,938
Some folks asked me about this this weekend. They suggested I cannot be 100 % certain that "Excess" nutrients do not cause algae. I mentioned: "I cannot test every cause of algae, thus I cannot ever be 100% certain. However, I can be virtually 100% certain of what something is not. At least to point where consensus and general laws, patterns are easily accepted by Scientific standards".
Testing involves setting up a design to see if a hypothesis is tenatively true or false.
We may never find the "truth" or be able to test every possible alternative to the cause of algae.
We can test individual and combinations of nutrients rather easily though.
Simply because a hobbyists has poor light or CO2 and doses nutrients = > algae does not imply the test is falsifies the hypothesis that excess nutrients does not = algae, they had confounding factors. This test does not enter into the statistical analysis. It must be redone and the test must be repeated.
If the hypothesis is excess NO3 or PO4 = algae, we must test the range of PO4 and/or NO3 to see. What is excess nutrients? Let's assume it's 20ppm NO3 and 5ppm PO4.
If we test a well planted tank with a good fish load, reasonable light, back up source of ferts in the sediment as well........this should be a good test up. For a control reference tank to be done, it must have no algae to start with.
It also must have ample head room for non limiting CO2.
We can use "blocks of time" for test replications if we lack multiple tanks also. So each 4 week test period = one replication etc. After a few years, we have a lot of reps and a lot of statistical confidence if we never get an algae bloom. Other hobbyists then report similar long term results.
This suggest is CANNOT possibly be due to excess nutrients = algae blooms.
This test does not say why nor imply why other people fail to have similar results.
It does not sat what causes algae either.
The only conclusion that can be made from the test is that we must reject the hypothesis that states excess nutrients = algae blooms in planted tanks. We then accept the alternative hypothesis, that something else is causing algae blooms other than excess nutrients.
Then we make a new hypothesis the test those alternatives and then go about testing them.
This is how we get somewhere in Science, little by little, step by step.
It is done with many test, sometimes we do get lucky, but that is very rare.
Hobbyists simply do not use standards and calibrated referenced methods for CO2, and very few measure light.
So how can you conclude much without doing that? Guess? You open yourself up to errors this way.
No matter what else might be going on, if the aquarium has no algae and I know I am adding excess ferts at these levels, I know it cannot be due to excess ferts. This I can know nearly 100%, even if I'm not sure about my CO2.
If you have algae, well, then ......you have some confounding issue.
This method does not help convince those who have trouble with excess ferts and correlation with algae.
But they have not confirmed their CO2/light either, so they are guessing without anything to back it up other than their own failings, lack of success. I think it is important to note, EI or excess ferts exposes weakness with light/CO2 balancing in the hobbyist horticultural skill set. If better management of light and CO2 are learned and mastered, then they can resolve the issue, this might takes a years for some, others seem to get it right off the bat. Still, limiting PO4 can reduce CO2 limitation and thus provide a method where the hobbyists could not fix the issue with CO2. But they still failed with CO2 and nutrients being independent, it does not change nor falsify the over all conclusion.
Regards,
Tom Barr
Testing involves setting up a design to see if a hypothesis is tenatively true or false.
We may never find the "truth" or be able to test every possible alternative to the cause of algae.
We can test individual and combinations of nutrients rather easily though.
Simply because a hobbyists has poor light or CO2 and doses nutrients = > algae does not imply the test is falsifies the hypothesis that excess nutrients does not = algae, they had confounding factors. This test does not enter into the statistical analysis. It must be redone and the test must be repeated.
If the hypothesis is excess NO3 or PO4 = algae, we must test the range of PO4 and/or NO3 to see. What is excess nutrients? Let's assume it's 20ppm NO3 and 5ppm PO4.
If we test a well planted tank with a good fish load, reasonable light, back up source of ferts in the sediment as well........this should be a good test up. For a control reference tank to be done, it must have no algae to start with.
It also must have ample head room for non limiting CO2.
We can use "blocks of time" for test replications if we lack multiple tanks also. So each 4 week test period = one replication etc. After a few years, we have a lot of reps and a lot of statistical confidence if we never get an algae bloom. Other hobbyists then report similar long term results.
This suggest is CANNOT possibly be due to excess nutrients = algae blooms.
This test does not say why nor imply why other people fail to have similar results.
It does not sat what causes algae either.
The only conclusion that can be made from the test is that we must reject the hypothesis that states excess nutrients = algae blooms in planted tanks. We then accept the alternative hypothesis, that something else is causing algae blooms other than excess nutrients.
Then we make a new hypothesis the test those alternatives and then go about testing them.
This is how we get somewhere in Science, little by little, step by step.
It is done with many test, sometimes we do get lucky, but that is very rare.
Hobbyists simply do not use standards and calibrated referenced methods for CO2, and very few measure light.
So how can you conclude much without doing that? Guess? You open yourself up to errors this way.
No matter what else might be going on, if the aquarium has no algae and I know I am adding excess ferts at these levels, I know it cannot be due to excess ferts. This I can know nearly 100%, even if I'm not sure about my CO2.
If you have algae, well, then ......you have some confounding issue.
This method does not help convince those who have trouble with excess ferts and correlation with algae.
But they have not confirmed their CO2/light either, so they are guessing without anything to back it up other than their own failings, lack of success. I think it is important to note, EI or excess ferts exposes weakness with light/CO2 balancing in the hobbyist horticultural skill set. If better management of light and CO2 are learned and mastered, then they can resolve the issue, this might takes a years for some, others seem to get it right off the bat. Still, limiting PO4 can reduce CO2 limitation and thus provide a method where the hobbyists could not fix the issue with CO2. But they still failed with CO2 and nutrients being independent, it does not change nor falsify the over all conclusion.
Regards,
Tom Barr