Aquatic eco system sells turn key units. This is what I started with. Just crunched their numbers for a starting point.
This whole cheap media stuff blows my mind. Why the hell would you keep rays and skimp on the stuff that is the backbone for their life support? I'm too cheap to buy fancy filters like bead filters but there is one thing that I will NOT skimp on and that is media.
I wouldn't use anything but K1/K3. They designed it and I'm guessing pattents don't alow for cheap imitations. BUT the K1/K3 is only most of the reactor, the other part is the chips that most people ignore, or just look past cause it costs too much. I haven't seen cheap knockoff chips and wouldn't be suprised if there's some out there, but I think overlooking this stuff is a mistake.
Cheap airstones don't perform like good ones. No different then the media we are discussing.
There's also a huge difference in opinion on how much flow to run through reactors. Manufacturers say low flow, slow rate, long dwell time. The people keeping fish utilizing these methods of filtration run higher flowrates under the idea that more tumbling can't hurt.
The whole concept of a reactor is to remove the less efficient bio bacteria. Life expectancy of bio is short. Once past it's "prime" it's less efficient then younger bio. A reactor tumbles media knocking off the old less efficient bio making room for younger more efficient bio. So instead of keeping a sump full of old tired bio that you hope is even still alive, you keep a sump full of spartans. Strong, efficient, and in thier prime. Everything else lays on the bottom till you crack the valve, then it's gone.
That being said if you understand the concept it's pretty easy to see that "more" surface area (like we are used to seeing as a good thing) really doeesn't mean better performance.
Seems reactors shape seems to play a part in media needed...... All you can do is experiment. Like I said, I just used Aquatic eco as a starting point, then tweek it from there.