I like a mix of everything, both rock and sand. The rock I like to mix dry base rock for the foundation that gets buried under the sand, and supporting structure. Then I like the branch and tabling rock that is more alive (some even dead, it'll all turn live soon enough). I like to save money for my customers as well as myself. Everyone I deal with can tell you I like to save, especially on rock. I don't see the need to buy all live rock ranging from anywhere between $6-$10/lb, depending upon where you buy it, it could even be more expensive. No names mentioned.
As for sand, I believe you're fine with 65% dry and 35% live there too. As a matter of fact, conversely to the rock scenario where the rock will all eventually turn live, not all the sand will. If you have a 3"+ sandbed, I don't see the lower depths of sand turning live. Maybe in some places where your inverts and sand sifting critters will turn the bed over and oxygenate the deep sand, most of it remains anaerobic (lacking oxygen) and won't turn live. The aerobic layer (topmost layer also called the benthic zone) will turn live and support life.
If you have any questions, hit me up. None of this is a trade secret. All published and ready for you to use. I've seen some people on the business side of the hobby treat some of these thoughts and actions as if they're top secret, you can't see what I'm doing, get out of here while I'm working on your tank, secrets, as if their business livelihood depends on them taking those 'secrets' to the grave with them
Give me a break.
Hope this helps,
Russ
