Thanks for tips everyone. I do have outline of the tank already made, and am using it for this task. I need to spend some time and see how each rock could potentially go with others, and thats my main issue. I just cant visualize things like that haha.

I kinda came up with one structure yesterday. It was complete fluke, but so far I like it (location and angle are not final). It did raise some questions thought that i wanted to inquire about

https://i.imgur.com/qbZyuVt.jpg
https://i.imgur.com/ezZaPfg.jpg

Few of the top pieces are barely touching one another, especially flat piece top right. How would you go about making this more secure? Even if I use glue and/or cement of some sort, there are very few points of contact between the 2 rocks. Should I try to build up shelf piece with smaller rocks using glue/cement and then connect to the bottom one, chisel away until it fits more securely, something else?

Since rock is heavy, and I have limited opening on the aquarium top due to acrylic brace, I will need to do this in 3 pieces. Once it is in the tank, should I connect all 3 pieces or leave them as separate? If I leave as separate, worried about one part falling over. If I connect, I wont be able to take out or remove if need be.

Thanks again for the help and tips so far.

Looks great, nice and open. Imagine water flow, crabs and fish bumping them, corals growing and shifting their center of gravity, the tank shaking when people walk by... The question of having the rocks easily removable or very stable is really a personal preference. Personally I lean toward stability, so I glue or cement my rocks. Others do the opposite.

drill holes and ty wrap once they are inside the tank. Or i've heard of drilling and installing acrylic rods. Me personally, i like to cement as much as possible. in your case i would cement two structures together and then try and make a sturdy resting point between the two and if you are still worried, drill for a single tie wrap you can install once inside. Easily cut-able down the road if you can remember where you tied it :mrgreen:


remember when you set the rocks inside the tank, Rocks first, then sand. that will be the main reason your rockwork shifts if it ever does.

i do have fiberglass rods ready to go, so i will drill and use those for sure with some rocks. Others i will super glue and cement together. Bigger issue is that between some of these, there are like 2-3 small points where rocks touch, so nowhere enough room to drill a rod and place, unless I want rod to be visible. Was thinking about zip ties, but heard the will fail and snap over time, especially with salt water. Will play around with it more and see if I can build up few of these to have more contact. Then I can cement them in place.

Thanks

I like to drill the rock and support it with acrylic rod, this makes it super strong. Then I use reef safe epoxy between the rocks to prevent them from pulling apart, you can even push small pieces of rubble rock into the epoxy to help hide it when you are done, after a couple months you won't even see the seam

What brand is reef safe epoxy?

Just the plain old two part sticks from any lfs instant ocean or the fluval one

Oh... that old stuff. I thought you meant real epoxy lol.

Instead of those two, you can use JB water weld or Loctite epoxy. It is same stuff but cheaper than ones made for "aquarium"