# DIY live rock how-to guide



## 50seven

OK, GTAA, many of you have been asking me about my personal experiences with my DIY live rock. There are many online guides and Youtube videos out there, which are a very good help and can show you how to do it; I'd suggest you check some of them out, as each of the techniques give a unique texture and style to the rock. I'll share what I did...

Wanna save some cash? The whole DIY live rock craze is simply making your own custom shaped rocks that serve the purpose of reef-harvested live rock without the ecological impacts. Though it takes longer to cure than natural LR, you can fill your tank for cheap $$$ and and do a real custom aquascape and rock walls.

Basically we're taking non-silica based aggregate and binding it together with Portland cement. But we want it to be porous, right? That's why we will also combine salt into our mix, as when cured, the salt will dissolve and leave empty pockets behind...

Please also bear in mind that any concrete product will take 30 days to cure, and cannot be used in a live tank until it had fully cured, as it will leech into the water and alter the pH quite significantly.

*Step 1: Pick your aggregate. *Use crushed coral or crushed oyster shell. A 50 lb bag gave me more than enough to do my 35 Gallon tank. Don't use brick sand or any other decorative sand unless you know it is not silica- based. Silica should be avoided in a SW aquarium in order to control diatomic algae growth. *I got my crushed oyster shell from my local CO-OP store for about $15.00* They use it to give egg-laying chickens more calcium in their diet.










*Step 2: Portland cement.* This will permanently bond the rock together. Use regular or white if you can get it, but it doesn't really matter. Once again, a 50 lb bag is more than enough, as you will only use about a third of the bag. See if you can bum some off of a bricklayer buddy of yours  Otherwise it's about 10-20 bucks or so a bag depending on size.

*Step 3: Pick your salt.* Use any salt you want; bigger grains is better than smaller. I used a 10 kg bag of road salt life this, and I still had some left over; cost was about $6.00. Lowes also sells a cheap kind of water softener salt that has large grains.










*Step 4: Mix it together! *This is the hardest part. If you can call it that. If you get this, you're laughing! Use the ratio of 2.5:1:2 for Aggregate, Portland cement, and salt, respectively. *First mix the aggregate and cement; then add water* until your mix is at a thick sticky consistency. You want to be able to form it into shapes and stuff, so don't add too much water or it will just slop all over. *Then add your 2 parts of salt*, and stir well, but for no longer than neccesary, as the salt will begin to dissolve if you stir it too much.

*Step 5: Make your rocks!* This is the fun part!  Ask your kids if you can use their sand box. Or just use it without asking. *Make sure the sand is damp.* Dry sand will not work. Make some interesting shaped holes and depressions in the sand, and then plop some of your mix in and shape accordingly. Get your hands dirty and have fun, but wear gloves if you have sensitive skin, because Portland cement is quite acidic.










*Step 6: Cure.* *Wait 48 hours* before you take the rocks out of the molds. Sometimes they can be taken out after 24 hours, but you risk breaking them. Submerse them in buckets of water *for the next 30 days,* changing the water about once a week or whenever you feel like it.

Once you set up your tank, be prepared that the pH may fluctuate for a couple of weeks; but I did this while my tank cycled, and I had no issues. I did my first water change about a week after my tank finished cycling and the pH has been stable ever since.

*Step 7: Seeding* *You will need to seed your tank with either live sand or live rock from another well-established tank.* LR rubble or sludge from somebody's refugium is great for this.

I think that the DIY live rock may be more prone to the regular algae blooms when a new tank is being set up, but I have not solid proof to back up this claim. It has now been in the cycled tank for about 3 months and is starting to show coralline growth.

That's all for now; I'll add more info as questions and answers arise.


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## Sunstar

would th esand imn th esand box not contain the silica that you wish to avoid?


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## explor3r

Sounds like a lot of fun, soon ill be making some rock.
Thanks K for the tread


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## 50seven

Sunstar said:


> would th esand imn th esand box not contain the silica that you wish to avoid?


Not much sticks to the cement - but it is another reason that you don't want your mix to be too sloopy. I started with smaller batches until I got the hang of it.


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## bigfishy

50seven said:


> *Step 2: Portland cement.* This will permanently bond the rock together. Use regular or white if you can get it, but it doesn't really matter. Once again, a 50 lb bag is more than enough, as you will only use about a third of the bag. See if you can bum some off of a bricklayer buddy of yours  Otherwise it's about 10 bucks or so a bag.


$12.79 for 88lbs at Home Depot, don't think I can even lift it!



http://www.homedepot.ca/webapp/wcs/...atchallpartial&Dx=mode+matchallpartial&s=true


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## 50seven

bigfishy said:


> $12.79 for 88lbs at Home Depot, don't think I can even lift it!


Sorry, my memory was a bit off. Bummer is, you will only need a third of that bag (or less) to go with a full bag of crushed shells. Maybe find someone else and share a bag!


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## solarz

It would be nice if a group of people got together to make a big batch of this, and maybe sell it for a low price?


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## 50seven

solarz said:


> It would be nice if a group of people got together to make a big batch of this, and maybe sell it for a low price?


I think that GARF already does this on a commercial scale. But I'd personally not do it for sale- though it was fun to make them, and I would definately do it again if I ever get a bigger tank, it was a lot of work. Fun work though,  something nice to do with the kids on a Saturday afternoon or something.

Though gettting together to do it might be a good idea if people are wanting to make some small batches, or just not confident to try it on their own.

Hmmmm, maybe I'll do a workshop this summer....


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## PACMAN

why do you add the salt?


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## Jackson

Is this cement a type that is not corrosive?

Most types we work with will burn the skin off your hands especially if your skin is sensitive.


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## Sunstar

you need to cure it for some time to reduce that corrosiveness

Pacman: To give it holes and make it more hollow/pourous


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## Jackson

Sunstar said:


> you need to cure it for some time to reduce that corrosiveness
> 
> Pacman: To give it holes and make it more hollow/pourous


Edit- sorry just saw 30 days.

So those 30 days is the min ammount of time I gather?


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## wtac

The 30 days and regular changing of the soaking water is to help reduce the caustic properties of the portland cement used. Same as in FW of soaking driftwood to reduce the leaching of tannins.

Portland cement when it hasn't properly "rinsed" enough has a pH of 12-13.


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## 50seven

Yeah, not sure if I mentioned it before, but gloves are recommended when handling cement products. I'm fine and it doesn't bother my hands, but if you have sensitive skin it will bother your skin...


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## UnderTheSea

Have a look at Bomix as they did carry silica free play sand and also had it in white. We ended up buying 25 bags of it just to have around for our DIY rock walls and rocks

We use water softner pellets and crush them up into smaller pieces. Who knows what you are getting in with that bag of road salt. Some people are also using pasta, but we found it did not disolved very quickly

For smaller pcs we put them in the toilet tank as this continuously flushes the water then on about day 21 we move to RO/DI water for a week doing daily water changes.


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## solarz

UnderTheSea said:


> For smaller pcs we put them in the toilet tank as this continuously flushes the water then on about day 21 we move to RO/DI water for a week doing daily water changes.


Huh, that's pretty smart (if a bit gross sounding ), certainly saves on water. I suppose you could also soak driftwood like that.


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## Zulfian

solarz said:


> Huh, that's pretty smart (if a bit gross sounding ), certainly saves on water. I suppose you could also soak driftwood like that.


remember driftwood leaches out a yellowish tea colour anyways... so new water might look like what you flushed down...


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## 50seven

UPDATE:

I did a workshop on this at the 2013 Saltie BBQ on the weekend... hope you all had as much fun as I did. Makes me want to start a new tank, but I think I'll stop right there. 

This thread needs more pictures, so here's some more from my 90G build thread. (This is from last year) *-Link to thread here-*

First came up with a simple mock-up of my desired rockscape, using the kids' Play-Doh:










And then took some eggcrate and the hot glue gun and made up some frames. I had some small PVC pipe that I melted with the heat gun to make a skeleton of my central rock tower.




























Ahh, there's some nice gooey messy cement! Looks like fun... My mix is 3 parts crushed oyster shell, 1.25 parts Portland cement (because I found that last time my rocks were a bit on the brittle side IMHO). After the cement is mixed, I add about 2 parts rock salt (I used half and half of water softener salt and road salt)










And I trowel it on to my frames. Once cured, these will be hard as a rock with no flex.




























This is fun...  Putting cement around the skeleton was harder than I anticipated. I ended up forming small chunks around a leftover pipe and then once dry I would glue them onto the skeleton, and then fill in the spaces with more cement.


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## 50seven

And a few more of the finished product.... Check out my 90G thread if you want to see what they look like now as the tank has matured.

Here's another shot from working on this very tedious tower rock thing:










These are from yesterday. Almost there; I'm really happy with how this is turning out.


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## Toofem

**

yay... Found it... I'll post pic of rock I made with you at BBQ last weekend when I crack into mine next weekend... I love your tower... I'm sure I looked at this thread early on and really wanted to do it... but I wanted to have a tank up and running more... 

I have been meaning to get some eggcrate for my montecap.... to set him + his pieces up top... maybe make a wee box with shallow sides... two pieces are on a plug tho, not sure if they'll fit... that's another thread... hehe


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## Bayinaung

question guys. These rocks - do these have the same biological hosting properties that regular live rocks do?


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## 50seven

Bayinaung said:


> question guys. These rocks - do these have the same biological hosting properties that regular live rocks do?


Absolutely! Just ask anyone who saw the cured rock that I brought to the BBQ...

Sent from my Galaxy Nexus using Tapatalk 2


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## Bayinaung

cool! I wanted to go to the BBQ. Just had family stuff to do that weekend.


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## aquatic_expressions

This IS AWESOME! Thank you for this write up and answering my question on my thread... I will try to post some pics tomorrow of the background I have made..


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## 50seven

Here's what the rocks I made last Saturday at the demo look like now... The salt had all gotten dissolved and the sun was shining, so I thought I'd let them dry out for a spell just so I could show what they look like


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## kamal

oh wow now I am super tempted to test this out......sweet looking rock


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## Toofem

*my rock*

Its not rinced yet...

But ill put it in bucket tomorrow... Can I soak it in untreated tap water?


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## 50seven

Toofem said:


> Its not rinced yet...
> 
> But ill put it in bucket tomorrow... Can I soak it in untreated tap water?


I always do...


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## Toofem

My rocks chillin while I changed up the water! Rocks made @ BBQ with 57! 

This is a great project!


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## TorontoPlantMan

Sorry to bring up such an old thread but what should the PH be when these rocks are done curing? I made a nice batch a couple weeks ago, maybe 2-3? but the PH is still too high for it to register even on my high ph test kit. 

Thanks


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## kamal

not sure of the answer to your question but those rocks look fab!


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## TorontoPlantMan

Really no one knows what the final PH should be? 



kamal said:


> not sure of the answer to your question but those rocks look fab!


Thank you


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