ttystikk
Nerd Gone Vertical
The aeration happens as soon as the water comes out of the waterfall opening. As it hits the water's surface, more oxygenation happens, along with breaking up any layer of scum that forms. Therefore all the oxygenation happens above the roots. If your roots clog the buckets that much, use bigger buckets! LolMy issue with using the buckets the plants are in to create the DO Is they are so filled with roots surface area would be limited. Creating the DO is a separate bucket and pumping it to the roots is a fail safe. I'm not a fan of using small hoses as they could possibly clog. I like big pipes to to let gravity keep every level and use the small stuff to direct the water
The size of the lines at the bottom doesn't matter as long as they keep up with the water flow coming in. I use several 1" outlets so if some clog the others will keep working. The smallest openings in the whole system are the 1/2” tees I use for the waterfalls.
Another way to ensure maximum oxygenation could be to use a venturi in the line between the pump and the waterfalls. That way you wouldn't need the second pump you're talking about using.
I try to use tub sites that are bigger than the plants need so they don't get root blind.