rsteagall:
Interesting thoughts on rubble sizing. I suppose, as I think we mentioned early in the thread, you could make the argument that rubble bottom tanks with larger rock pieces could be a form of BB (at least aesthetically)...But I think the similarity ends there. We're talking about not being afraid of detritus accumulation in the rubble zone, as it may actually be of benefit to the organisms living and "working" in there! Yes, we embrace protein skimming, etc., but I think it can be safely stated that we're departing form the "conventional" BB methodology somewhat. Perhaps the "rubble bottom" is really a sort of "fusion" of several schools of thought.
I do like the GARF stuff, and you are right- they have been advocating this type of thing for some time. However, as we've discussed, although the cryptic zone idea is a very important part of the rubble zone methodology, it is also a biotope to model. BTW- I love the "CZR" term...!
I suppose it can also be argued that rubble could be anything from the 1/2" size that you mention, all the way up to small chunks of rock. My thinking is that even 4"-5" pieces of broken slab can, if stacked on the bottom of the tank, be considered "rubble", or at least comprise a "rubble zone".
I think that we can stretch the working definition of "rubble zone" to something like: " A concentration of various-sized pieces of calcareous materials, loosely stacked upon each other at varying depths for the purpose of increasing biodiversity, creating a functional habitat for fishes, encouraging the production of supplemental food sources, and fostering natural (denitrification) processes."
Yikes- that's a seriously long definition! But, I think it covers some of the stuff we've been disussing here. "CZR" certainly is easier to write! LOL
In the end, I guess we really cannot take ourselves too seriously- we're just a bunch of fish geeks trying to have fun! And I tell ya- the ideas in this thread are just soo cool to see!
Lots of different ways to run a rubble zone system, I think!
Keep it comin'!
Scot