This statement is almost as misleading as some of those from that book published in 1978
There are many fish species which live in stable natural waters, Rift Lakes being the obvious, but not the only
Yes, this is true and the fish have no control of whether they encounter stable pH. Likewise, there are many fish species which do not live in stable pH waters. Amazonia fish, which comprise the bulk of the ornamental fish hobboy are an obvious example of that. So where are we with this? Just because a fish or a plant is found in an area with a particular characteristic it does not automatically follow that those characteristics are a prerequisite for survival and it does not automatically mean the characteristics are even a requirement. It is often the case that hobbyists have been taught to put the cart before their horse. Rift Lake fish live in a more stable pH water as a direct result of the waters alkalinity. Since it is not possible to have a natural body of water that has high alkalinity with a low or widely varying pH it is automatically assumed that the pH is important, when it really isn't.
It is more instructive to consider Amazonian fish which DO move from one body of water to another in search of food and as a result of the seasonal change in rainfall which often dumps large quantities of organic acids into the water. The low alkalinity of the water results in wild swings in pH without any damage to the fish.
What pH lovers always seem to ignore is the fact that the fish are much more concerned with the characteristics of the substance that enters the water which may have an effect on the pH. Their response is to the
substance, not to the pH. If the substance is toxic it will harm the fish, if the substance is not toxic it will not harm the fish regardless of the pH change that results. There is also the case where substances change their toxicity depending on the pH of the water. NH3/NH4 is a typical example. Again, the damage is a result of NH3, not as a result of pH.
It amazes me that not only Dupla, but members of this forum and who use CO2 fail to recognize the obvious inconsistency with trying to maintain stable pH concurrently with stable CO2. It should be obvious that at normal alkalinities, there is no way of achieving this. Using a pH controller, for example maintains stable pH but at the cost of unstable CO2.
It also amazes me that after decades of using CO2 and observing the unstable pH that is inherent in it use, that anyone should question whether stable pH is a relevant goal.
So my question is, do you use CO2 and have you observed short term or long term damage to your fish resulting from unstable pH? Hobbyists kill or injure their fish due to CO2 overdose quite frequently, but I see no evidence of damage due to unstable pH.
Do you have any peer reviewed scientific published articles to this statement?
Well, again, here is another disappointing state of affairs. I'm being asked to provide peer reviewed scientific published articles but Dupla gets a free pass based on their anecdotal experience? Where is Dupla's peer reviewed data?
So if Dupla can keep their substrate from becoming anaerobic long term using heating cables and if the rest of us non-believers are also able to keep our sediment anaerobic free long term, what does that say about heating cables? Doesn't it imply that heating cables don't make any difference? If you've read anecdotal data on both sides then this disproves Dupla's contention that the cables are a requirement. If the cables were necessary, wouldn't it follow that those who do not use the cables would experience a higher incidence of anaerobic sediments? Clearly this has not been the case.
For peer reviewed data you might try Plant Physiology's 1994 study of Oxygen production and transfer to roots:
http://www.plantphysiol.org/content/plantphysiol/105/3/847.full.pdf
This was also followed up with additional research published in Plant, Cell & Environment, by Professor Ole Pedersen (of Tropica) in the 2004 article
http://www.plantphysiol.org/content/plantphysiol/105/3/847.full.pdf
Dupla's claim is that the currents produced by the cables are necessary in order to bring Oxygen to the roots. Clearly this claim is false, because we know that aquatic plants transfer Oxygen and in fact they create their own little world around the immediate vicinity of the roots where toxic substances are oxidized and aerobic bacteria colonize the area. These articles are just a small sample.
Dupla made rather significant contributions to the planted aquarium hobby
Yes, of course they have, but does this mean that they are infallible?
We can also consider that they have actually hampered the development of the hobby by charging outrageous prices for their products and by not offering more realistic education.
Please note that I have not bashed Dupla. I have merely stated the facts as we know them now and have pointed out the errors in the video. Tomorrow, we will know something else.
Have I ever purchased their products? No, because I could not afford it at the time and neither could many other hobbyists.
The inability to move forward with a hobby due to lack of funding constitutes a hampering of the hobby. Ask any any researcher and their peers.
Cheers,