Titanium or plastic to support rock stack

[jccaclimber]

I'm currently located near Dallas, TX and have free stacked rock work which I like in a ~600 gallon system. I'm moving to near San Francisco, CA and expect to have the main display tank in storage for a while. I have two concerns:
1) Earthquake proofing the rock stack.
2) Remembering how the rocks are laid out. It took me a solid week of work to get them how I want them, and I want to get them back in as close to have they came out as possible.

Other than tagging and taking lots of pictures I think drilling the rocks for rods as I take them out.

1) Does this seem reasonable?
2) Would I be better off with 1/2" plastic (polycarb/acrylic) rod, or 4 mm grade 5 titanium rods?

Larger rods would have more bearing area against the rock, but also be a weaker material (I haven't compared shear energy yet).

 

[cwalton00]

Everyone I know uses acrylic rods. No sense in putting titanium in the tank.

 

[davocean]

I use acrylic rods, 1/2" or better, use the next size up from what you go w/ in a
masonry bit.

My structures withstood a 6.3 we had years ago.
Any bigger quake I'd be more worried about glass failing than structures.

 

[jccaclimber]

That's good to know. I'm thinking polycarb is a better than material than acrylic due to the higher impact absorption?