DIY Rock Formation

[OneDummHikk]

I read through the archives and the only places I found mention of trying to make your own rocks I saw comments about them being ugly. What has me thinking about trying to make my own are that I simply can't find rocks the right scale and dimensions to create the look that I want. The look that I want is a canyon look leading into a cave. If I take rocks and create the canyon on each side of the tank (my 12G nano), then I need a piece that will go across the top of the canyon sides across the back. The piece would have to be 16" long or so. For me to get a rock that size to cut it up to make that ledge, the rock would cost me 100 bucks minimum. So, what I thought about doing is taking crushed coral, crushed oyster shells and making my own agrocrete type mix and making three rocks formations. One for each side canyon wall and then one for the "ledge" to go across the top of the cave entrance. It would have to be in three pieces so that I could get it into, and out of, the tank. The tank has a euro-style brace across the top.

I already have the crushed coral and crushed oyster shells. I could get coloring for the cement in purple. I considered even adding some green into it. Mix everything good, without the coloring, then put the coloring in it and not mix it completely so that it would have patches of purple and green.

After getting the basic structure to it, use live rock rubble to cover it so that you see the lr but it is sitting on my base rock DIY structure.

Thoughts/comments?

[chrischris]

sounds like it would work but make up a small batch first to try out your color idea so if you dont like it you dont waste a whole batch

[scoop]

There is a lot of information on making agrocrete on the garf.org website. I read something there about using pasta shells, too to make the rock more porous.

[OneDummHikk]

Originally Posted by chrischris

sounds like it would work but make up a small batch first to try out your color idea so if you dont like it you dont waste a whole batch

That is true. The rock formation won't be 12x16x8 (thats about the tank size). So I wouldn't be mixing up a lot anyway. The other thing I had thought about doing was making a batch of purple and a batch of green and then simply mixing it as I placed it.

[aquawolf]

Originally Posted by scoop

There is a lot of information on making agrocrete on the garf.org website. I read something there about using pasta shells, too to make the rock more porous.

This is where I had read about doing it a while ago and was going to recommend the same site.

[OneDummHikk]

Originally Posted by scoop

There is a lot of information on making agrocrete on the garf.org website. I read something there about using pasta shells, too to make the rock more porous.

I read about the garf site in the archives. If adding the LR rubble on top of my structure, do I really need to worry about the porous part? It doesn't have to be part of the filtration itself if I can get enough LR in the tank itself. I bought 16 pounds of base rock yesterday and tried to come up with the canyon effect and I couldn't get it to even come close to looking right. What the DIY formation would be is something to hold the LR in place without it wanting to tumble down.

[aquawolf]

Originally Posted by OneDummHikk

I read about the garf site in the archives. If adding the LR rubble on top of my structure, do I really need to worry about the porous part? It doesn't have to be part of the filtration itself if I can get enough LR in the tank itself. I bought 16 pounds of base rock yesterday and tried to come up with the canyon effect and I couldn't get it to even come close to looking right. What the DIY formation would be is something to hold the LR in place without it wanting to tumble down.

Eventually your base rock structure will become live rock and act as part of your filtration anyway. You should be able to form it where it will hold what you want it to, but it can still be porous in areas. Holes here and there for fish to swim in and out of and frag plugs to fit in would help you out a lot in that design. Of course, this is just my opinion.

Heck, I might not even worry about coloring it. It may take quite a while, but I am sure coralline algae will eventually grow on that too.

Good luck with whatever you decide.

[OneDummHikk]

Originally Posted by aquawolf

Eventually your base rock structure will become live rock and act as part of your filtration anyway.

That was actually my thinking when I bought the base rock. Save the money and let it turn into LR.

Originally Posted by aquawolf

You should be able to form it where it will hold what you want it to, but it can still be porous in areas. Holes here and there for fish to swim in and out of and frag plugs to fit in would help you out a lot in that design. Of course, this is just my opinion.

Ever seen the buildings that have concrete facades that have the rocks in the concrete showing? The pour those walls lying down, sandblast them to expose the rock, and then stand them up. What I was thinking about doing is sandblasting the rock formation after I got it finished. Thats what got me to thinking about the coloring. Not sure what chemicals are in the coloring agent though. I will have to call a friend at the concrete company tomorrow and find out for sure. If there is anything proprietary in it, he will still tell me for what I want to know.

What I may end up doing is what I started out to do and that was using rubble to build it with in a dry state, then glue it together. The base rock I bought I paid too much for it (2 dollars a pound) and there is only one piece larger than a baseball. It is the flat piece I found for the ledge across the top of the cave entry. I was too tired to argue with him about it but I should have.

Originally Posted by aquawolf

Heck, I might not even worry about coloring it. It may take quite a while, but I am sure coralline algae will eventually grow on that too.

Good luck with whatever you decide.

That was the idea behind using the base rock was to let it color up over time. I can get LR rubble for 3 dollars a pound at a different LFS. The only thing with using LR is that it is wet and makes gluing it together a little more difficult than using dry base rock. Heck, I think I will call the other LFS in the morning and see what he will sell me dry base rock rubble for. If LR rubble is 3 a pound, he may sell me base rock at a dollar a pound. Even then, with the 16 pounds I bought yesterday, and guessing at it, it will take close to 30 pounds to do what I want to do.

The more I think about it, the more I realize I need to think about it some more

[aquawolf]

Randy, I may not have stated it correctly, as what I meant is that your home made aragocrete structure will eventually become live as well. The rock facade thing does sound really cool though, I can actually envision your vision if that makes any sense.

[OneDummHikk]

Originally Posted by aquawolf

Randy, I may not have stated it correctly, as what I meant is that your home made aragocrete structure will eventually become live as well. The rock facade thing does sound really cool though, I can actually envision your vision if that makes any sense.

Yeah, it makes sense. What I keep going back to is how to do the surface of it. I have even thought about getting 2 or 3 cans of Krylon paint and splatter painting it. Instead of a solid even coat, just splatter it. I have a sand blast booth but it is in Alabama. I think I am going to just get a bag of cement, make a template for my tank and just make one and figure out the problems as I go. I can get the same effect of sandblasting (not exactly but close) by rinsing it the same way they do exposed pea gravel concrete. As it sets up, you rinse the cement off the top and exposing the aggregate in the concrete (hence the name - exposed aggregate).

[OneDummHikk]

Something I just read about again in the archives was pH swings with DIY rocks. Anybody have an recollection how bad they will be and how long it takes for it to settle down and stabilize? And, what is it that causes the swing? The cement mix or the rock itself? I am guessing the cement mix itself.

[dobejazz]

Originally Posted by OneDummHikk

Something I just read about again in the archives was pH swings with DIY rocks. Anybody have an recollection how bad they will be and how long it takes for it to settle down and stabilize? And, what is it that causes the swing? The cement mix or the rock itself? I am guessing the cement mix itself.

Thats what KIA is waiting for now the PH to drop on his DIY rock

[Loverotties]

It's going to depend on the size tank how much rock and how dence the rock is,alot of varibles.

[OneDummHikk]

Originally Posted by Loverotties

It's going to depend on the size tank how much rock and how dence the rock is,alot of varibles.

Quantity of Rock.
Makeup of Rock.
Shape of Rock.
Water quality used to cure it with.
Frequency of water changes.
Temperature of water.
Epsom Salt (if used).
Quantity of water used to cure it.

What other things will affect the curing time?

[OneDummHikk]

Originally Posted by dobejazz

Thats what KIA is waiting for now the PH to drop on his DIY rock

I saw his thread. I am trying to figure out what all will impact the curing time to see if there is any of it that I can help mitigate the time a little bit. I know heat will play a part and I think kia's will cure quicker with some heat in his tank. The heat helps the salt dissolve and help it get out of the rock quicker.