did you make live rock?

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did you make live rock?

Postby tzenda on Mon Mar 07, 2005 9:52 pm

has anyone here made their own live rock using portland cement and crushed oyster shells? just wonderin, i have been readin on it and it sounds like a good deal except the amount of time to cure. But all good things are worth the wait,,, Right :wink:
Your body is not a temple, its an amusment park. Enjoy your time there.
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Postby causeofhim on Mon Mar 07, 2005 10:30 pm

I thought I've read multiple posts about it on RC. Some people were trying it and others commented on how it leaches harmful amounts of somthing, cant remember what, into your tank over time.

With the cost of rock, I would give it a shot for base rock if it was safe.

Let me know if you research more.

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Postby mfd78 on Tue Mar 08, 2005 7:45 am

Would you really have to cure it? I mean, it's not like it's going to have die off or anything. Do you mean it just take a long time for the bacteria to take up residence and begin acting like live rock?
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Postby Sula on Tue Mar 08, 2005 8:03 am

I always assumed that curing for home made rock referred to drying time for the cement mixture, or is that not correct?
What I've never understood is what you do to make the cement porous enough...do you add air bubbles or something, and if so how does THAT work. Could get pretty messy - sounds like a summer/outdoor type project.
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Postby MattK on Tue Mar 08, 2005 8:43 am

DIY rock needs to cure in water because it leeches things into the water. It also has a very high PH for the first 6 weeks.

Here's a link to ReefCentral which describes how it's done:

http://www.reefcentral.com/forums/showt ... ystercrete


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Postby tzenda on Tue Mar 08, 2005 4:15 pm

yea, i have read all those treads and the curing means in fresh water to get it to leach out all the bad stuff,

yes it would be a outdoor or basement project,

all you really do is mix 1part portland cement with 4or5 parts oyster shell and mix in only enough water to get it to stick together nothing more, the more water you add the denser it becomes and less porus.

you can make whatever shapes you want (branches, caves, shelfs, holes for coral plugs, ect). once it sets for a day you then begin the curing or leaching process, which is to soak it in fresh water or even vinegar ether way it take a 4-6 weeks to complete leaching(small amouts could be placed in the toilet tank if you have never used disinfectants it there) you need to change the water out at least onece a week

once its done you have a custom rock made just for your tank and you and your kids (gread kid project by the way) can be even more proud of your tank.
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Postby meisen on Sat Mar 12, 2005 11:49 am

I have made a bunch of rock that way......had over 200 lbs in one of my old reefs. I couldnt see the point of bringing it out here with me however and sold it on ebay for 400.00 (it was cured and covered with coraline).

I would be happy to help you out if you want. I actually want to make a bunch of frag plugs which you can do with the same formula. I just need to make a mold for them (or find the right plastic popsicle trays)

This is what worked for me (I just sort of mixed until things worked so go slow and just have fun with it:

approx 5 parts southdown, 2 parts crushed coral, 1.5 parts portland and 2 parts water by weight. You will read lots of formulas in the RC links but that is what worked for me. Add the water very slowly, mixing constantly as you go so that you dont flood it. Add a lot less water than you think you should since adding more dry mix after flooding it doesnt work well (makes crumbly rock). When the consistency is very thick and all wetted out, you are ready to mold. I liken the correct consistency to day old oatmeal. It will set very fast (15' or so) so make sure you have your molds ready to rock before you start putting water in.

I did my molding in a concrete mixing tray but coolers work well too. Lay down some southdown in the container, dampen it and then shape it like how you want your rock. Use a stick to make projections and indents into the mold. Add your mix and shape away. Try to push some sand into the mix so that you have some hollow spaces. Your first few pieces will likely be crappy but as you practice, it will improve. Dont be afraid to experiment as your raw materials are super cheap.

Make sure you keep your mold container moist and warm. I just covered mine with a bit of water and a plastic bag. The concrete will suck up a lot of water as it cures so this is key. Lower temps=slower cure time. I had no problems with curing at around 60 degrees but it took a full 2 days.

When they are finally hard, you still have to cure them for use in the tank. I just soaked mine in rainwater for a couple of months, adding some vinegar to the barrels every few days. You can also just leave them outside for a season and that should take care of it. You can test the alk of RO water placed with the pieces. When you get 0 or near 0, you are cured.
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