More than Niko just swimming against the current, I think he is on to a very important point here. We so often hear about algae problems and immediately blame light, CO2 management, nutrient excess or deficiency, lack of water changes, take your pick. Many of us hardly ever think of inadequate biofiltration as a possible cause. I am so impressed to have read so many thoughtful discussions on filtration in this forum more so than other sites I frequent. I think if more hobbyists discussed filtration, we would be better off.
To share some observations, I have learned a lot about filtration from my outdoor pond which relies completely on a giant UG and bog filter-- no fancy UV, bead filter, or any external filter for that matter. What's interesting is I get very little algae to start the season (even before plants are established) and even less as the season wears on despite increasing light intensity, temperature, nutrients/organics, all factors that should encourage algae. Unlike many NPT, it's definitely overstocked. No water changes ever. Just autofill evaporative losses. I don't cover half the surface with floating plants according to pond gospel. I do seed frequently with bacteria.
So why is this giant fishbowl in the hot sun not full of algae? Not from my sparkling maintenance routine, that's for sure. Despite my best efforts, this tank has established a balanced ecosystem.
The answer is not absolute turnover volume. I have played with turning the waterfall low for a week with no ill effects. The answer I think is the superior biofiltration of the system as a whole aided by constant surface agitation/oxygenation, surface skimming and proper mixing/flow. The few pockets of algae I get are in areas of stagnation-dead spots. There is an aerator going 24/7. Organics are quickly skimmed off the surface or carried down to the coarse 3/4 to 1.5 inch non-compacting gravel substrate which, thanks to the full length UG filter, acts as a 'living' substrate that effectively processes waste. This pond does not have the usual mucky bottom. Likewise, the bog filter favors the cultivation of a robust micro fauna that enhances root uptake by the vascular plants. Like all filters, it works even better when flow is slowed down to a point.
When we move indoors, the conditions are reversed. Unlike outside, we can fully regulate lighting, temperature, nutrients, CO2 (mostly). What we don't often regulate well in our tanks is filtration. Many substrates are pretty good but gas exchange often suffers over time with root systems/plant health along with it. Could this be why a mature tank can suddenly become not so stable at some point? Should we be stirring the substrate more often now that UG filtration is passé in planted tanks? Is vacuuming really bad for plants?
And, external filters leave much to be desired. HOBs clog. I have owned a number of different canisters in the past and, set up in the standard fashion, they clog too quickly with the usual reduction in flow, channeling, and inefficient contact with microorganisms, dare I say maybe even some counterproductive things going on. The newer ones are only too good at telling us how poor our flow really gets when not maintained regularly.
So, does the OP help advance the hobby? Absolutely. It should open our minds to better possibilities in feeding our bacteria. How often should we dose bacteria? Is flow adequate in our tanks or is our pump underpowered? Can we direct flow in our tanks better and oxygenate the substrate better? Probably. Filling canisters with fewer things apt to clogging and more and coarser biomedia is a good start. The fluidized bed filters look promising. I have switched to sumps in the past year or so and have found them to be immensely less problematic with more possibilities. My 100g display tank has a 45g sump that doubles as bog filter/grow out tank. It can house far more media and a more powerful pump than a canister, so it works for me. Can there be a bog filter in the tank? Sure, in a riparium setup as many are doing or like in the paludarium I just set up.
Forgive my inexcusable rambling and I do not mean to stand on a soap box. I think many of you have many better answers than I do. I just like that topics like the OP give way to many questions.