Rock arches... Or rock-adjacent

[SueAubu]

I've got a build going on and a lot... A LOT... Of acreage to cover in a 10ft x 4 ft tank. (500 gallon)

We've already reinforce the floor from below realizing how heavy this setup is and will be once 7000+ lbs of water, sand, tank and base are assembled. I also have lice rock holding my reef in a 220 gal and a 100 gal., so I'd like to do what I can to minimize the weight I'm going to have to add in additional rock.

The tank is deeper (30") than my lights will reach (24"). I need to figure out a way to elevate my reef rock above the 24 in level. I was thinking to do that with arches that can act as foundation for the live rock above it. This will give the fish room to swim (maybe leaving the corals alone?? Hahaha, right) and hide.

Does anyone have recommendations for sturdy arches? Lightweight, if possible? I've looked at limestone, lava, Aqua Forest, Real Rock, Caribsea. I like the limestone's added benefit that it will help the pH. I like the lava, except most of them look like they're pieces together and may crumble under weight.

Ideas? Suggestions? Advice? A cousin in New England breaking down their tank?

Thanks!

 

[Waters]

If you aren't against dry rock I would go with Marco rock. It is lightweight and very pourous. It can be broken up and glued/cemented into whatever shape/size arches you want.