DIY Rock Help

Discussion in 'I made this!' started by meagan1823, Feb 17, 2009.

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  1. meagan1823

    meagan1823 Purple Spiny Lobster

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    Ok I am wanting to make some rock and had a few questions.
    Does it matter what kind of cement I use? About the only kind around here is quickrete. Will this work? If not what kind do I need? What is unhealthy for an aquarium that the cement might contain?
    also the only sand around here is sand box sand and it has silicate. Is this ok to use just to hold the cement mold? Can I use it in the mix without any ill effects?
    Also I was thinking about useing crushed lava rock in the mix. Does this seem like a good idea or not?
    Thanks
     
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  3. reefnut1

    reefnut1 Spaghetti Worm

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    I used portland cement and sand (I dont remember which kind) for the rock that I made in the past Quickrete is the brand that I used.

    If you mix in macaroni with it toward the end of the mixing process it will make the rock more porous (spelling?) The macaroni will wash out as the rock cures and leave small openings. I used all different sizes when I made the last batch.
     
  4. trelane

    trelane Peppermint Shrimp

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    Crushed lava rock often contains heavy metal, thats a definite no. Quickrete is ok, but you might want to mix it with calcium/argonite sand. After doing some research, I've determined that Quikrete has gotten lazy, and adds in sand. You're better off with calcium based sand instead of premixed. Something about you're giong to need the calcium anyway!! Also, mix some rock salt into the edges of the concrete. As it dissolves it'll increase surface area.
     
    Last edited: Feb 17, 2009
  5. jbaker

    jbaker Feather Duster

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    Quickrete is the brand, get the bag which says Type II. Lava rock is a definite no-no. Go with the aragonite sand and use additional sand or crushed oyster shell in an appropriate sized box to form your mold. Crushed oyster shell is usually available at Farm/Ranch stores or feed stores. It's used in livestock feed as an additive. Make sure you let the rock cure for several weeks before you put it in your tank.
     
  6. meagan1823

    meagan1823 Purple Spiny Lobster

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    Where do I get aragonite sand from?
    The only pet store I have around here is Petco.

    I own horses and goats so I can readily get Oyster Shells.
     
  7. meagan1823

    meagan1823 Purple Spiny Lobster

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    Also, our Lowes and Home Depot only carry Type 1.
    Will this work?
     
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  9. cloons411

    cloons411 Plankton

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    type I will work just needs longer to harden
     
  10. JasonSquared

    JasonSquared Spaghetti Worm

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    2-3 parts solar salt (for water softeners) to 1 part dry portland cement. Use a little sand or other aggregate, and mix water in it until it's the consistancy of cookie dough. Add water or mix until it this consistancy. It should pile up when you form it after mixture is complete.

    Then allow it to dry for 24-48 hours. It will be slightly brittle at this point, so be careful to not break it when you do the next step.

    Cure the rocks in fresh water for a month... You can do this in a stream, or I have heard of people doing small quantities in a toilet. But you need to change the water frequently because as the PH rises, it becomes less effective at curing the concrete. You should cure until your freshwater doesn't get above a pH of 10 or so no matter how long it stays in there... At this point it's safe to add in your tank. (Don't worry it won't make your tank water go to a pH of 10 due to the fact that the ALK in the Saltwater prevents its dissolution from the rock.

    The water will dissolve the rock salt in the mixture levaing behind a very pourous and realistic rock that you can shape in many different forms.
     
    Last edited: Feb 19, 2009
  11. meagan1823

    meagan1823 Purple Spiny Lobster

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    Thanks.
    My only trouble is finding Sand that doesnt have silicate in it.
    Do I have to use any sand in the mix? or can I just use crushed oyster shell?
     
  12. convict3

    convict3 Astrea Snail

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    i used portland II crushed oyster shells and salt. this was my first 55 gal tank i made all the rock in this tank except 2 small pieces
     

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