The Ultimate DIY Rocks!

[WmTasker]

ive have a question Ive read that adding the salt last works best, well I wasnt thinking when I made my test batch and added the salt early, I did 2 parts crushed oyster shell, 2 parts salt 1 cement. well im looking at the rock in water and Ive noticed that the cement had covered the salt crystals and the salt has dissolved now there are hollow molds made of cement where the salt crystals were. any ideas?

I was worried that the salt in the middle of the rock wouldn't disolve right away and would later leach in to my tank causing problems. Has this happened to anyone or does it all completely disolve during curing? Did the ratio of 2:2:1 work? (brian.julia) do you have any pics?

 

[WmTasker]

Good info. Thanks. That conforms to what other folks have told me who work with cement. FWIW, thats how I made my diy rock and its in my tank now. Not the most artistic but it works. It sat in water much longer only because my stand and plumping were not ready. Here's a shameless plug.

What was the ratio of materials used to make your rock?

 

[brian.julia07]

Ill put a pic up soon, What I'm talking about is when the salt crystals were covered with cement the cement hardened. the salt then dissolved. the cement is still there in the shape of the salt. I started touching the rock and the little salt exoskeletons started "popping" because they were hollow. Kind of like when your shrimp sheds there is an exoskeleton left. its hard to explain ill go grab my camera and see if I can get a pic of it.

 

[brian.julia07]

ok here are some pics, the cement is going to be a dark color because it has never been dried out. I also noticed that most of theses pockets have popped by themselves but some have not yet.

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here is one that i popped before and after.

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So it looks as if its going to turn out fine I think!

 

[rharr21]

FWIW, I have not read all the posts in this thread, but would like to comment on the use of perlite and possible toxicity. In the horticulture/floriculture production industry it is common knowledge that pelite as a soil amendment causes symptoms of fluoride toxicity in plants in the Liliaceae and Marantaceae families. These media generally have a pH of 5.5 to 6.5 and it is likely that the multitude of organic acids in these media increase fluoride solubility. If soil pH is increased (with lime) between 6.5 to 6.8 fluoride becomes tied up in the form of calcium fluoride and leaches out of soils during irrigation. That being said, reef tanks are not potted plants and the pH of a tank is basic. And I don't know if fluoride is toxic to marine life. Just something to think about.

 

[Rhodes19]

ive have a question Ive read that adding the salt last works best, well I wasnt thinking when I made my test batch and added the salt early, I did 2 parts crushed oyster shell, 2 parts salt 1 cement. well im looking at the rock in water and Ive noticed that the cement had covered the salt crystals and the salt has dissolved now there are hollow molds made of cement where the salt crystals were. any ideas?

Salt does a good job of making pockets in the rock but I think the bigger issues of using salt in the mix to make rock is that the holes they leave are big but have a smaller surface area for bacteria to grow, where as smaller particles used in the mix offer more surface area for bacteria which we want. Another drawback that I have read about and experienced, is that rocks made with salt tends to be much more brittle and more likely to break/crumble. I made one batch with salt out of curiosity and it crumbled fairly easily. I didn't use that batch for my tank. What I do like using the salt for is for the texture it leaves on the rock. Kind of lunar landscape. I'll use it for making molds and that worked out kind of nice for me. HTH

 

[Rhodes19]

I was worried that the salt in the middle of the rock wouldn't disolve right away and would later leach in to my tank causing problems. Has this happened to anyone or does it all completely disolve during curing? Did the ratio of 2:2:1 work? (brian.julia) do you have any pics?

The salt will disolve away while its curing in water. Remember, cement is pores so water will flow throught it.

 

[Rhodes19]

What was the ratio of materials used to make your rock?

Hi Billy,

I used a 4:1:1 ratio. 4 parts crushed oyster shell, one part type 3 portland cement and mixed them together dry, then I slowly added 1 part water to mix. Depending on the consistancy you are looking for and the humidity in the air you may need to add more or less water. If you have senitive skin, you may want to wear gloves while you are playing with the dry cement. It can give a little chemical burn to some folks. I did make a batch using aragonite (ame ratio), but at over $2 per lbs, I went with crushed oyster shell at $0.18 per lbs.

 

[juldelf]

Hi everybody
i just fall on this thread
how does this thread works cause there's lots of pages
is there a resume somewhere
I find some pictures on internet and i'd like to know if somebody can explain which methods they used

 

[juldelf]

 

[juldelf]

 

[Mrrealmadrid]

I need some advice...

I am doing some work in my basement and there was some cement work going on. Long story short I got a bunch of pretty cool pieces that were chipped off during the work and I would love to use them in my tank....

I am not sure of the brand of cement that was used and I am afraid that stuff will bleach out... If I soak them with vinegar will all be ok?

Any info would be awesome

Raul

 

[stormrider27]

From what I have learned from this thread once the concrete had fully cured all you really have to worry about is PH. Place the pieces in water for a couple of days and see what happens to the water's PH.

 

[JoelNB]

Mrrealmadrid, the vinegar would only begin to dissolve the cement. You'll need to wait for it to finish curing on its own. Keep it in water.

 

[stampe]

I am getting near to start a new 95g aquarium. I want a rock background in the aquarium. I have read almost the entire thread, and I find the idea of making DIY rocks and background very interesting.

A lot of different opinions of the ideal mixture exists. A quite dry mixture is used by many, by dripping it into the mould in order to achieve a porous rock. Many explain how this creates a light rock that you can pour water directly through. Many people in this thread recommend not to use salt, as the rock can become brittle. I can see that adding salt in the dry mixture, that later on is dissolved will make the rock brittle, as perhaps half, of the already light and porous structure will disappear when the salt dissolves.

IMO a very porous rock do not sound ideal, as the goal is to create a oxygen free environment inside the rock where anaerobe bacteria can live. If the rock is too porous, there will be too much flow through the rock, creating an aerobe environment, and the filtration effect of the rock will disappear!

If a more liquid mixture is used, with salt to make the rock porous, the rock might become solid enough to withhold, and still porous enough to create living space for anaerobe bacteria!

Well, I might become wiser after some experience and drop the salt, but my logic just tells me that a rock where water can run unhindered through is too porous.

Feedback is welcome.

 

[goldmaniac]

that is a good thought.. that pourous rock is useful mostly as an aerobic zone and a place for copepods, all pods, to hide and reproduce.

but i'm guessing that some spots would also be an area for anaerobic bacteria as well. Some.

I made rock with salt, and i always figured that there were spots PAST the aerobic areas, like a back room of a cave, that would be anaerobic. I've broken some rock apart to look inside and there have been multiple 'chambers' in a row, where a piece of salt was touching another piece, touching another piece, which touches the surface of the MMLR.

 

[JoelNB]

IMO a very porous rock do not sound ideal, as the goal is to create a oxygen free environment inside the rock where anaerobe bacteria can live.

As the water passes through normal live rock, the aerobic bacteria deal with ammonia, etc. This uses up the oxygen in the water. Inner parts of the rock may therefore be anaerobic.

If a more liquid mixture is used, with salt to make the rock porous, the rock might become solid enough to withhold,

This is not an option. You must prevent the salt from becoming too wet until the cement begins to set.

 

[stampe]

As the water passes through normal live rock, the aerobic bacteria deal with ammonia, etc. This uses up the oxygen in the water. Inner parts of the rock may therefore be anaerobic.

I agree, but the water needs to be almost stagnant inside the rock to become anaerobic. My own live rock containts water offcourse, but the water does not just empty out imidiately when lifting it out of the water. I therfore doubt that the very porous DIY rock will become anaerobic inside.

This is not an option. You must prevent the salt from becoming too wet until the cement begins to set.

And that is a bit of a challenge i guess.

What are the experience with DIY salt rocks, do they just crumble into rubble after some time, or are they just more fragile.

What about making a salt rock, let it cure for a day, and then covering it with a layer of non salt DIY rock by the drip method to add strength to the rock, and the inner part has a better filtration effect.

 

[JoelNB]

Let me just say that I made Insane reefers Old Skool Plus recipe. Combined with my bed of builders sand, these always keep nitrates at 2 or 3ppm.

http://www.reefcentral.com/forums/showpost.php?p=11531293&postcount=12

 

[Rhodes19]

What have people's experiences been after putting their diy rock into their tank? I made 200 lbs and put them in my 180. My water parameters are:

pH 8.5
Ca 480
Kh 5
S.G. 1.024
temp 77

They were soaking in fresh water for 3-4 months with water changes. I figure I'll have to do some hefty water changes to get the parameters in line. What has every one else experienced?