One of the reasons I was asking...and I could use your guys advice
Tom told me the new guy might not eat for a few days or even a few weeks.
I only plan on having the octopus in the tank with live rock.
Im afraid the live rock will die-off with no feeding and waste being produced.
In the past with seahorse tanks...
Ive actually "fed" the live rock on sparsely crowded tanks.
Giving small amounts of cubed frozen food that could break down and keep-up the bacteria on the live rock.
Hard to know how much though.
PVC is fine to use. We make enrichment puzzels out of it.
An octopus that does not eat for a week would be a concern. However, in a reef tank which likely has lots of small crustaceans hiding in the live rock, it is hard to know if a new octopus is eating or not.
Lack of bioload is not something I would worry about.