using concrete to stabilize rock formations?

[kelrn98]

I have done some searches and found several interesting threads about using pond foam & sand to creat rock structures w/ dry base rock. however, I about 350-400lbs of live rock from my old 110g and 120g which I am combining to put in my new 300g. I would like to create some rock wall like structures w/ pvc and light filter grid sheets to cover the overflows. I know I can come up w/ a supportive device by gluing the PVC and zip tieing the light filter (whatever its called). I plan to zip tie some of the smalller rocks to the pvc and light filter grid, but I would like to use a cement like product to fill in the gaps and possibly cover the zip ties. Is this possible? How long must the cement cure before placing in the water? How long can LR be out of water before significant die off? It is fully cured at this time because I have had all of the rock for many years.

Another idea I have is to build PVC structures for areas other than the overflow w/ 1/2 pvc, secured w/ pvc cement; I used a large masonry bit to drill holes in some of my larger rocks and would like secure/stack them by sliding the pvc through the holes. Does this sound practical?

Any suggestions or links to associated threads would be great. I really don't want to just stack my rock in the tank. I dont mind that whatever I build will be semi permanent, in fact I'd rather it be that way. I had some issues w/ rocks tumbling down and cracking a tank in the past. This tank is 8ft long and was a PIA to get into my house. I don't think i will find any volunteers to help with that again, lol. Also, the tank is 31 inches deep and off the floor 42'' so it's not really practical for me to be reaching into the tank to change to rockwork anyway.

thanks for any help, I plan to start the rockscape on tuesday, my next day off.

[herring_fish]

Aragocrete is used for sand molding and attaching rock together. Most of this is done with dead, dry rock. You can pour Aragocrete slurry in a box of aragonite sand and it ends up, having a layer of the sand on the outside. It is hard to picture but you can pour in a shape, add a thick layer of sand over parts or the slurry but leave other areas uncovered. Then you pour in more Aragocrete followed by more sand. You can repeat this to make all kinds of structures as the uncovered areas form connecting columns. This way you can build the shapes that you want.

Putting concrete in the tank will adversely affect the pH and kill what you have in there. It needs to be put in a kiddy pool of water for six to eight weeks, as I remember it, with daily water changes from the garden hose. GARF has been doing this for quite a while so please go to there site and read all about it.

I don't think that you can take live rock out of the water for very long at all. Bacteria will live in the areas that stay wet. The rock is typically very porous so it should support that bacteria for a longer period of time but what is on the surface will die when it dries out.

You could use Aragocrete to build structures with custom rocks and dead rock to make arches, tunnels, walls and the like. You could build a long dead structure with a series of pockets like soap dishes where you could place lots of live rock and corals securely. These structures can get covered with coralline algae just like regular rock.

Aragocrete forming is cool to see pictures of but it is not for everyone.

[kelrn98]

Thanks for the info. I have been working on my set up since february and I just don't think I will have the patience to wait that much longer. I will have to come up with some formations with my LR only. Maybe my next build, lol.

[herring_fish]

I bought some and played with it but it wasn't for me either.

[JustinDF]

Never tried it. Definitely different