concrete live rock for walls and ledges

[karimwassef]

re-posting here - here's how the rocks looks about a year and a half later

[vhhjb]

To anyone looking to do this... One of the most painstaking efforts is washing the pumice and oyster shells. Do not underestimate this work.

[karimwassef]

Originally Posted by vhhjb

To anyone looking to do this... One of the most painstaking efforts is washing the pumice and oyster shells. Do not underestimate this work.

I agree.

Here are a few more learnings:

I would have also used LaCl in my cure cycle to extract residual phosphates. Even with a lot of washing, I still had a GHA grow out that could have been mitigated.

I don't see any negative side effects of using pumice. Green coralline seems dominant vs pink, red or purple and I wondered if the pumice gave the green some advantage, but that's conjecture.

I would have ensured full concrete coverage of the cloth in making my "clothcrete". In some cases, I had run out of concrete before cloth and was too lazy and/or cheap to whip up another batch. This resulted in poor coverage at the very end. I regretted that. The cloth needs to be saturated in concrete.

In some cases where the cloth was exposed, I had to remove the rock since some fish (blennies) feed by nipping/grinding at the rock and any excess cloth would cause be consumed. This led to a stomach obstruction and then death. My blennies are fine today, but I removed any rock that wasn't fully covered.

I would still drill holes all over, but the attachment with airtubes was harder than I expected. The openings would get filled and were hard to see after some time with life. The holes ended up being excellent pod refuge access tunnels. I see bristle worms and pods use the hidden networks of PVC and eggcrate extensively.

I wouldn't run the rock wall all the way up to the overflow. While aesthetically pleasing at first, this had a few negative side effects:
First, it gave access to a lot of crawling (non-swimming) life to the overflow. In fact, the small space between the overflow and the rock seemed to have become the preferred hiding location for crabs/shrimp/starfish/snails and small fish. I'm not sure why but I suspect it's the combination of fast water flow/oxygenation and the small space providing refuge from larger animals.
Second, the algae on the lit side of the clothcrete was very hard to remove for the tangs and even snails and crabs. Big fish don't like to be so close to the surface and even the strongest have a hard time accessing this highest zone. I have a surge that raises the water level by a couple of inches and my biggest tangs time it so they can get to this area during the high water line sideways to access the algae there.
In the future, I would rather use a suspended glass lip that's 3" lower to hang my rock walls from.

I would create more sandwich zones. So, in some cases, I would allow the clothcrete to fold back on itself creating small caves that were nearly invisible. This was another favorite hiding place. I would intentionally use eggcrate spacers and make more of these thin water zones.

I love the rock suspension. My sand bed is so much more effective with almost complete water access instead of rock on top. However, I didn't expect the difficulty that this can create for some creatures. Hermit crabs especially suffered since they would fall off the rock and then have no easy access to the rock city hovering just out of reach. They're not super smart... I added enough sand and small rocks to create ledges for them... Small snails had the same problem once they fell in the sand. They had to go all around to the glass walls before gaining access to the ShanGrila hovering just overhead.

I was worried about the surface integrity, especially under the grinding gnawing of urchins. They certainly removed the surface sand wherever they could, but the concrete held. Any areas I was lazy with concrete coverage, they gnawed through but that was a minority since I had already removed most after the blenny incident (see above).

Less is more. As my corals grew out, I realized that I had too much rock surface. I don't have much rock volume, but I did create a lot of surface. My encrusting corals live it, but plating or branching corals struggle against each other (wife says I bought too much). Next time, I wouldn't look at the design as a complete work with the rock. It's only complete with the corals growing out. The best way to look at it is like making a model of a tree... I made the whole tree, when I should have just made trunks and big branches.

I would have covered up some of the surface with acrylic or plastic sand. Coralline seems to prefer plastic instead of the very porous clothcrete. It grows there but much slower. I would have used a paintbrush to selectively create some patches where I wanted fast coralline growth.

I was concerned with some of my more ambitious shapes that were convoluted and turning back on themselves. These have been my greatest successes. After a few months, the light/shadow effect allowed life to create natural zones and these look the closest to random natural structures. My more mundane platforms still look like mundane platforms...

While I don't know the side effects, I would have used the internal PVC structures to redistribute flow. I was hesitant to do this, but I will try it next time. This is especially true of the side and back walls where return water access may have been straight forward. I have coral growing directly on those plates now, or I would have already taken them out and replaced them with return surfaces.

I'll add more as I think through my learnings here.

[Marinus]

Originally Posted by karimwassef

re-posting here - here's how the rocks looks about a year and a half later

Wow, talk about a DIY build! I very much enjoyed going through this thread. Thank you for taking the time to post images and share your build along the way.

Love how it turned out. The way the fish freely flow through the aquascape is just mesmerising. Way more interesting and fun for both fish and viewers than the standard aquascape styles.

Very impressive!

[karimwassef]

Thank you. It was a labor of love (and some pain).
With what I've learned, I'm looking forward to the next one.

[karimwassef]

for the evolution of the concrete wall, follow it here:

http://www.reefcentral.com/forums/sh...8#post24202398

[bryhan67]

Nice Camo..

[karimwassef]

[gregkn73]

Very beautiful scape, with great results and useful info to improve it further.

[karimwassef]

thanks. I'm planning a new tank and working with a new medium for the backbone structures.

My biggest mistake overall was making the rockscape too thick so it would look good from the beginning. It had a very open structure inside (that was good), but I didn't want a "skeleton" structure with thin ribs.

Going back, that's what I should have done. Less is more... it should not look good in the beginning, or it will be very overcrowded at the end as corals grow out.

[karimwassef]

Here's a magazine with a condensed version -

http://www.reefhobbyistmagazine.com/...5-issue-38.pdf

[MrGuy]

Really well done planning and telling of your story. Kudos!

[WLachnit]

That's a great unique look that you don't see much in reef tanks. While I read your article I didn't read the whole thread, so forgive me if you've already discussed this. Is it thought to get good flow such that you don't have dead spots?

[karimwassef]

No. Because it's all man made, the rock is almost all elevated off the sand and the area behind the rock is just as open as the area in front. While it looks dense, it's actually very open since the rocks don't actually need to sit on one another for support. I have 4 x WP60s, 2 return lines at either end from a Jebao DCS 15000 and a surge that releases from each end also separately.

So I have lots of flow, but not because of the rock work.

[WLachnit]

That sounds great!

[ratherbeflyen]

I love artistic creations like this. Trying to find a new and unique way to stack a pile of rocks is really boring and all look the same. Good job.

[karimwassef]

Thanks. I'm now entering my minimalistic phase

I want to see how to create floating and elevated thin structures so that corals occupy more volume that rock... it's a challenge, especially when the starting structure will be very spartan.