The Ultimate DIY Rocks!

[GuySmilie]

<a href=showthread.php?s=&postid=9891458#post9891458 target=_blank>Originally posted</a> by Insane Reefer

Guy, you didn't mention any pre-kuring handling. How long from the time you mixed the cement, to the time you put them in water to kure? What sort of water volume to rock ratio are you talking about? If you used cold water for kuring, and never any hot, and the pieces are large and thick and you didn't have any water movement, you might still be seeing salt, but it is more likely to be C-S-H, the stuff that is being chemically made from day one to supposedly day twenty-eight (give or take, of course), and the main thing we are purging from the rock to bring the pH down. Salt should form definite crystals if leaching out of the rock with moisture, not a powdery substance. Neither C-S-H or salt are particularly harmful if ingested, you could always use the tip of a finger to dab up a small taste - like cops do to test suspected drugs on TV. That's how I figure out if most of the salt is out of my rock - taste for salty.

I let them harden for 7 days in the mold before putting them in the soak. Was probably about a 4:1 water:rock ratio for the soak. Always used cold tap water. It's been more than 45 days since they were cast. The substance I described previously definitely had a crystalline structure, not powdery. I almost did the wet finger test but the table is under some trees and with the birds and all....you know

 

[airinhere]

I am curing mine in big deep ponds that I have access to. its cold, but I never have to do water changes. I read that the white stuff leaking out of the rock was some sort of magnesium based compound. (The post was a few pages back in this thread) Thats why I am looking to just dissolve the stuff away in an acid bath. I believe (and could be wrong) that the lime is present everywhere in the cement and is what is forming the hardness and strength of the rock. Insanerefer has a point about interupting the chemical reaction of the lime and the potential for this to weaken the rock. My hope is that the cement has become hard enough in a two week period to be acceptable. A soak in the acid to dissolve the remaining lime and magnesium precipate and you should have a clean stable piece. (I hope). As far as the salt is concerned, I also remember reading that the salt can take as long as 3 weeks to dissolve fully. I think the writer (earlier in this thread) was mistakedly refering to the magnesium precipate. Salt dissolves in minutes in water and I hope the porosity of the MMLR allows the water to saturate the salt and allow it to diffuse out in just a few days of time. As far as pre curing, I wait three days after sculpting my pieces. All that time, they are packed with salt (often literally buried in the stuff). I then pull the pieces out of their salty cocoons, tie them to a rope and carefully lower them into my pond. (Its deep, cold and has a stone bottom).

 

[airinhere]

Doahh, There are some good ideas rolling around right now on how to try and speed up the cure time for the DIY rocks. Right now its a minimum one month wait from the time their made until you could even hope to put them in your tank. And after seeing the precipate events in my first couple of attempts, I would make sure the ph is stable and that nothing else is still reacting in the rock before you put them in your tank. The rubbermaid containers are still alright, but I had thick white precipate everywhere from dosing calcium and soda ash into those while I thought I was just trying to match the params of my tanks. 10 dkh, 420 ca. I never even got close before I had major issues, the water looked like milk for a couple days. After the Ph settled down a bit, I was able to balance everything easily. Now my rocks are already being covered in coraline algae. Poured Dec 26, finished curing the last week of Jan, in my tanks since then. (well thats for one of my tanks, the rest went in at about 2 week intervals since then.)

 

[Doahh]

I'm fine with the 1 month....
I just want to know what to put in it like at first it was half and half protland cement to rock salt...
What is it now?
How do I actually make the rocks in the first place?
I just think paying 4 bucks (For a rock) a POUND for uncured rocks is REDICULOUS



Hey you live in sacramento...
What LFS have you been to?

I've been to
Capitol Aquarium
O Street
Your Reef (My Main Store now)
and Aqua Life Aquarium

 

[Doahh]

oops I forgot... could I just leave it in the rubbermaid trashcan for 2 months?

And after I put it in my tank and seed the cycle with some other live rock this rock will become live when the cycle is over?

 

[Doahh]

OK so if I have this right you:
Mix up the recipie (portland cement rock salt and oyster shells?)
Let it dry for 24 hours or the curing time
put it in a trash can full of (fresh or slat?) water for 28 days
wait a day
than a 24 hour acid bath?
Than I can put it in my tank and start the cycle?

 

[airinhere]

There are no real set measurements for what portions of salt to cement to sand. I go with a mix of 90 lbs of cement, 100 lbs of salt and 25 lbs of aragonite sand. I use these measurements cause thats how the materials are packaged. (pour a whole bag in). I use as little water as I can get away with. I sculpt my pireces one handful at a time and use salt to fill in areas that will be caves and ledges later on. When I finish, I leave everything to dry for three days and then carefully spray the salt off my pieces with a hose. Then I put the pieces directly into my pond. I leave them for 4 weeks to cure, but usually get impatient and pull my pieces during week number 4. I soak for another week in saltwater from waterchanges that I store in big rubermaid storage containers.

After ph has stabilised around 8.3 then and only then put the rock into your tank.

The acid wash is still experimental.

I work at Exotic

 

[Doahh]

are you serious 100 lbs of salt?
or is it a typo and only 10?
I have GOT to get down to exotic... I live way up in loomis

 

[Doahh]

so it really takes only a month?
I thought it was around 2

 

[Tahlequah]

It can be anywhere from 4 weeks to 6 months.

 

[Doahh]

hmmm... i better start now

 

[airinhere]

You read right. 2 bags of the salt at 50 lbs each and a full bag of cement. I also pour a half sack of aragonite sand into the mix. I do pour everything together dry and mix well. Then I slowly start adding water. The real wait is after everything settles in and the rock is in your tank. I figure about three months before you see any coraline growth and six months before I would think the rock is really "live". (performs effective denitrification and such.)

 

[airinhere]

Um.. I just went looking for the post I thought I saw on this thread about the white salt looking stuff that slowly forms like stalactites on the rock. I would have sworn I read it was tested by someone and found to be a magnesium based compound. But I cannot find this info and want to make sure everyone knows I am cautiously retracting that data. (but I still think the acid bath will disolve the stuff anyways.)

Also, I want to know if I missed something about the group consent about the best/optimal ratio of cement to sand to salt. I have been kinda 'winging it' and just doing what seemed about right with the safest materials I had available. Are there benefits to using more or less salt? Is there any real need to continue using just aragonite sand or would oyster shell be just as good? I am very leery of silica sand, but does it really matter?

Just seems like the recipie changed so often, I just kinda started doing my own thing and maybe there is a better way.

 

[Tahlequah]

My current batch is 2 part portland type I or typer III cement, 1 part crushed coral (some people have even left this part out), and 3 parts water softener salt (crystal kind, not the pellet type).

Some people have used Quikrete, but i dont think the gravel looks very natural but to each thier own. Others use argonite sand which is about the same as the C.C. but a bit smoother.

The one thing that you need to make sure of is the salt, preferably it should be in crystal form, and it should also be NaCl (Sodium Cloride aka Salt) and not MgCl (Magnesium chloride ) or KCl (Potassium Chloride).

 

[airinhere]

Are you using the solar salt from home depot that comes in the big blue bag? Thats the stuff I have been using.

I found another DIY rock thread here on reef central (looking for the reference about the white precipate stuff) One of the guys there tried the acid wash and said it worked for about 2 days. Even the Garf site seems reluctant to promote acid washing as anything but a good way to clean your rock and make it more porus. They did suggest drying a piece of rock out and then acid washing it to get the rock to absorb the acid like a sponge. I fear this would cause serious issues with weakening the structure of the rock.

 

[Doahh]

so how much would all of this run me expense wise?

 

[silverwolf72]

50lb Oyster ~ $8, 40lb Concrete or Portland cement ~ $3-$5, 40lb Solar salt was around $3-5, 40lb playsand for mold was another $4. All in all I think I spent like $20 materials + equipment. look at the last page I posted a pic.

 

[Insane Reefer]

http://www.cement.org/tech/faq_DEF.asp
Airinhere - these are the crystals that you are probably thinking of, although salts can do sort of the same thing in cement and it is called Efflorescence.

Doahh. Figure it will take 2 months to make your rock - if it happens sooner, Yea!, if not, well - it does typically take 6-8 weeks (with very regular water changes) unless you can kure in an open waterway

The recipes haven't really changed - just what particular people like to use. You need to keep your ratio of cement to "whatever" to around 3-4 to 1 (3-4 part "whatever" to 1 part cement)

If you go back to page 1 or 2 of this thread break, you will find the "Superlong Post" - read it over - it covers a lot of stuff - I would repost it, but my PC dies yesterday and I don't have ready access to the copy I post.

And as far as acid, acid currently is not an accepted way to cure, however most folks who have tried have tried while the cement was still "hot", or chemically reacting. My theory is that with "finished" rock of more than 28 days, the acid bath at an appropriate strength will dissolve the softer high pH stuffs and release them quicker in the kure bath. As far as I can tell, no one has tried it at this later stage - only up-front, trying to cheat as it were.
I will post my results.

 

[Doahh]

about how many pounds of what will I need for my 90 gallon? I'm trying to get my list together...
I currently have set out to buy:
45 gallon rubbermaid pond
90 lbs protland cement
100 lbs solar salt from sams club
100 lbs oyster shells...

mix
3parts Oyster shell, 1 part Portland, 1 part Solar Salt


The big question... is it OK to use tap water?
What kind of portland cement?

OK my plan is the ultimate..
I'm going to get a cardboard box with the same dimensions as my tank. I will then assemble my under gravel jet system and my PVC Overflows. I will then build the rocks OVER the under gravel jet system. Bam instant integrated jet system

 

[skimmerman100]

ive tried making rocks but it is better to buy it. its a good idea for people that have a small or limitted budget