Pretty much agree with most of it, that is 11 points. It is one of the more "down to earth" myth buster articles I have read, but I also think they purposefully, as persuaded by my own paranoia, left out material so to make their case more persuasive, which is quite typical in these type of articles.
They also should have made a point about myth busting the notion of "slopped bottom ponds".
From my perspective, a few thoughts on 4 out of the 15 points :
Article Point #7 : You should dip your new Koi in a suitable chemical bath before introducing it into your pond ....
If you buy your Koi from a reputable Koi only dealer – and you should NEVER buy Koi from a Garden centre or Aquatic chain – then the Koi will have been properly quarantined and treated for parasites and rested for at least a month to ensure that it is healthy when collected and free of disease.
True, however, they willingly over look the concern of "old pond" syndrome and the facts that those koi are leaving the Dealer's pond disease and parasite free, which is not the only reason to quarantine new fish.
As all ponds age, they create their own "ecosystem", which will contain various concentrations of contanimants and other unknown microorganisms and water chemistry that other ponds will not have. The fish already in the pond has adapted to the "old pond" conditions. However, this does not mean a new fish will instantly adapt and remain healthy to the "old pond" conditions.
If the new fish struggles adapting to the new pond's "ecosystem" and water chemistry, then this stresses the fish, which inevitably lowers its immune system and osmoregulatory abilities, and then this leaves the initially "disease free, parasite free" fish extremely susceptible to infections from very basic microorganisms that healthy fish easily overcome and the "old" fish in the pond easily overcome as well.
Irrelevant from where the fish came from, they should have still recommended to quarantine the new fish in a seperate tank with "old pond" water, not with a chemical bath, and the tank preferably with another fish from the "old pond". If any problems should arise, then it will be easier to treat the new fish in the smaller quarantine tank environment with the proper treatments.
Article Point #12 : Pumped filter systems can be just as good as Gravity systems.
It’s a no brainer.
Sure, if there is an assumed design in play here on both sides...
Also, the author conveniently leaves out the disadvantages, which are quite costly to some pond owners, to gravity systems. Gravity systems require the main mechnical filtration pieces to be below the pond's water level. This means these components will have to be in a pit or the pond will need to be a raised pond, which both can be quite expensive endeavors dependent on the owner's context.
Nowadays, there are options out there there that have perfected the pump-driven filter systems (such as the zakki sieve + MC50), which avoid the oxtail soup and tiny suspended solids. Even without these devices, a S&G filter (which gravity flow systems also often have after the settlement chamber), which is easily cleaned out with a blower, will work quite fine at removing those tiny suspended solids after the pump, that is as long as the water prior to the pump is fed through a prefilter (which there are above ground options available and can be easily DIY'd) without restricting the pump too much.
Even after a settlement chamber, which a properly designed and installed one can be expensive as well and area consuming, there is still tiny suspended solids. This is why there are quite often polishing pads or another "device" used to further refine the water in the gravity flow system.
Just like with any system, even including gravity flow systems, there is a right and wrong way to design them all and they each require the appropriate equipment. When properly designed, pump fed filter systems do not require anymore maintenance nor more expensive UV devices than a gravity fed system.
Article Point #13 : Aerated bottom drains are the best way to aerate a pond and improve the efficiency of the bottom drain.
I think their concerns are exaggerated and entirely dependent on the type of bottom drains installed and the type of diffusers installed.
As far as the aeration impact on pulling debris to the bottom drain, when the aeration was off, I have seen fine debris accumulating a few inches away from the bottom drain. When the aeration is turned on, I absolutely have seen experimental trials of sand accumulations being swept into the bottom drain.
If the aerated bottom drain is causing murkiness due to tiny particulates remaining in suspension, then this means the filtration lacks polishing devices, which a settlement chamber is not a polishing device.
Article Point #14 : Its best to turn over the volume of the pond through the filter at least every hour.
As with any general rule, there are situations that change them, called exceptions to the general rule.
Obviously, when the biological filtration is failing, then there will be growing ammonia and nitrite reading. Obviously, when there are more fish in the pond, then there will be more production of ammonia and nitrite. So, at any time they register ammonia and nitrite, then they only increase their biological filtration or reduce the number of fish in the pond. Hmmm... They apparently are not aware of the chemical engineering idiom, "pollutant equilibrium".
Filtration will only process what it is given and the "turn over rate" is the volume that is given to the filtration. When the pollution created in the pond is equal to what the filtration receives from the pond to process, then there will be an equilibrium reached in the system. There is a point, dependent on biological matter or fish or filtration capacity or pond turn over rate, when this equilibrium favors the pollution volume and so there will be an increased reading of pollution.
There are very good reasons why highly stocked systems, such as one 14" inch fish per 50 gallons, have a higher turnover rate and it is not due to poor filtration devices.
I do not like the term "overstocked" since it assumes far too much. Also, when someone says their pond is "quite heavily stocked", as the author has done, without additional details or a very quick concise sentence as to what they think is "quite heavily stocked", they are often blowing smoke in the reader's eyes.
