By this I mean, they have a heavy bioload, use lots of skimming and suppliments to keep their reef in balance
Lots of people with 'heavy' setups do use skimmers, but it is not the only way to do things, even with such a setup. I go back to Mr. Borneman. This is someone who feeds his fish, corals, and inverts heavily and effectively uses no skimming.
Going skimmerless with a heavy bioload is probably harder to do than using a skimmer. With a skimmer, just plug it in, tune it and watch it suck tons of stuff out of the water. When using biological nutrient management, you need to ramp up your feeding gradually in order for the bacteria and organisms in your tank to keep up with the increased load.
there are still debates as to what exactly the skimmer is removing and whether its good or bad
Its very true that we do not know what exactly a skimmer is removing. I would not phrase it as good or bad exactly. It really depends on what you want to do with your tank.
On my previous reef tank I went back and forth several times and I always saw a reduction in sponges, foramineferans and feather dusters when I turned on my skimmer. Skimmers remove what would otherwise be food for these organisms, and may well also remove larvae.
Skimmers most definately remove very fine particulate mater and this stuff is food for many organisms, including coral. These organic flocs are also coated in bacteria; also a major source of food for some organisms.
For example, I have a free swimming harpacticoid copepod in my refugium that is quite abundant. The main food for harpacticoid copepods is detritus, and for a free swimming pod like this it would be small floating particulate matter. If I use a skimmer, I am directly 'competing' with my pods for their food source. Since I want these pods both as a food source for other things and for biodiversity in general, I am happy to give up my skimmer.
This is not a matter of right or wrong, good or bad, but a queation of what organisms and foods you want in your tank and why. Skimmed and skimmerless are both valid methods for maintaining a reef tank. Each method has advantages and challenges.
Fred
