The Ultimate DIY Rocks!

[Insane Reefer]

<a href=showthread.php?s=&postid=9175331#post9175331 target=_blank>Originally posted</a> by Rhodophyta
I think one of those additives is powdered aluminum which produces "air" in reaction to the wet concrete mixture.

Is this safe? My MSDS says that aluminum compounds are incompatible?

Remember your WWII history. If the Normandy Invasion had failed, the next step planned would have been to build huge troop ships from lightweight concrete and regular concrete for a frontal invasion.

Actually had forgotten that - didn't learn it in school, but from an old pair of codgers who talked about "how I would have won the war", and then later I heard about it once in a while from table top wargamers...

I think white portland is made from a different color of limestone.

It could be that too - limestones do come in lots of colors, but mostly it is the gypsum.
Here is the MSDS for the white cement I use:
http://www.lehighwhitecement.com/pdf/msds_portcement.pdf

...hit the almost hardened rocks with a power washer, you can expose the aggregate, giving the illusion of white.

Alternatively, you can use a sand blaster when it is all done, and sort of make the rock look more shaped by water, if you see what I mean, as well as bring up the white aggregates. Also, a acid wash works to bring up aggregate details too...

I also have a question for those who are familular with MSDS sheets. It says like one page 4 or 5, that the pH of the cement in water is 12-13. Does this mean when it is fresh mixed? Because I have rocks that have kured out and when tested in salt water read anywhere from 8.0 - 8.8. But if I test them immediately after curing/hardening, they do read 11-14...

 

[Aqua Keepers]

<a href=showthread.php?s=&postid=9189680#post9189680 target=_blank>Originally posted</a> by speckled trout
rufio173, good point about the really nuisance algaes! Hair algae bites, in my book.

However, one concern of coralline is that it decreases the biological filtering capacity of the rock by covering the openings of the "pores" in the rocks. In doing so, it makes it less able to "filter" the water, which is the main reason why most of us say we want it in our tanks to begin with.

Personally, I don't really worry about that too much and would much rather have coralline outcompete bryopsis than worry about it losing a little filtering capacity. That's what my skimmers are for; to take up the slack!:bum:

I was just gonna reply to Rufio's post with the same thought on it preventing filtration which is going to be very important in my case. I'll be doing a BB tank. So, no bio filtration from a sand bed. I'll also be going with minimal LR in the aquascapeing, but my rock panals should make up for that. As far as the nuisance algaes, should'nt we be takeing care of that by keeping low nutrients? Maybe we should start a new thread: The Great Coraline Debate.

 

[speckled trout]

I have a deep sand bed and lots of rock. I have tons of biological filtration and quite a few "algae patrolers" who constantly keep an eye out for any algae that they can get ahold of to munch. These include hermits, tangs, and several barnacle blennies I caught off an oil platform who love anything green. I also employ two skimmers to remove any organics that aren't taken care of "naturally"

But, back to the coralline issue, the people who are trying to make a more "natural" colored rock are, in the end, just gonna ask themselves why? The coralline will cover their best efforts! They'll eventually be asking themselves why did I bother??:hmm5:

Also, really try to find a river or lake to cure your rock in it'll greatly decrease the level of work involved. These will be much more able to adequately move the huge amounts of water that are really necessary to properly cure your rock. However, I prefer moving water because it exchanges the water more and keeps the sediment off your rocks so that they'll cure completely.

Anyways, have fun with thte shapes and make some cool rock.-Mike

 

[KyleP]

I tried the 4 to 1 mixture of water softener salt to QuickWall Quickrete the other day and it did not work. Waaay to brittle. I'm going to try a 2 (salt), 1 (cement), 1 (sand) mix next time. The rock looked good though! Unfortunately it was nothing but holes. I think I can cut back on the salt and still have very porous rock.

 

[Insane Reefer]

<a href=showthread.php?s=&postid=9201333#post9201333 target=_blank>Originally posted</a> by KyleP
I tried the 4 to 1 mixture of water softener salt to QuickWall Quickrete...Waaay to brittle.

That quickwall is a hydraulic cement, isn't it? Might have more trouble with it and salt mixing, and fubar'ing the batch.

I'm going to try a 2 (salt), 1 (cement), 1 (sand) mix next time.

I never have had luck with the cement/salt only mixes. My preferred recipe is 1-1.5 part cement + 1.5 part sand + 1 part crushed coral/puka shell mix + 1 part salt, but this is expensive to make - you could use oyster shell in place of the CC/puka to bring the price way down. It still makes really porous rock if you cast it right, and it is not fragile.


Good luck and post some pic's!

 

[jjoos99]

I made up some using some of the smaller white water softener salt and it also crumbled apart. I used some oyster shells with it. I didnt have this problem with the clear small solar salt. I dont know if it was a bad mix or it had something to do with the white salt.
Jeff

 

[em805]

Anyone know if Quickwall and oystershells will work for making rocks? Just asking since, it sounds like quickwall is easier to sculpture but, maybe I missunderstood.

 

[lildraken]

coralline

coralline

<a href=showthread.php?s=&postid=9187300#post9187300 target=_blank>Originally posted</a> by PolypHead
could be your water parameters. Different parameters can affect coraline growth significantly. hows your calcium and Alk?

good point! my alk is 8 dKH and my Ca is 400
I have 8x54 T-5's lighting in a 110 gal.

Maybe i'm just impatient. I personally love the beautiful purple and pink colors of the few specs of coralline algae that I do have. I don't think that could ever be a nuisance since I already scrape the glass every few days.

 

[Beenalongtime79]

Hey all,

It's amazing how a good protein skimmer can lessen the load on your biological filtration.

With a good protein skimmer, good husbandry, good flow to keep detritus in suspension and bare bottom tank, your tank could survive for decades.

By using a powerful protein skimmer, you shift most of the work to the protein skimmer and less on the sand bed and rock. I personally think the sand bed acts as a detritus and chemical trap, but that's me, you don't have to agree. I've used both and I really like the BB better, the amount of crap my skimmer pulls out each and everyday makes me less likely to go back to a DSB, and I feed a very sparse amount of food. Much easier to maintain in the long run. I don't like the look as much as one with a sandbed though. I might drop in a 1/2" coarse aragonite sandbed in the future and change it out every year or two depending on how the tank is doing. It's just hard to maintain the thing without being in the same physical location as my aquarium (parents maintain it with ease now that it's BB, just clean the skimmer neck and feed the tank. ).

Whether you use DSB, BB, medium sandbed, etc., the best thing you can do is to get a good protein skimmer for the tank, and get some good flow going.

Anyways, keep on trucking and keep those phosphates low!

Peace,
John H.

 

[Beenalongtime79]

<a href=showthread.php?s=&postid=9192954#post9192954 target=_blank>Originally posted</a> by pito
I was just gonna reply to Rufio's post with the same thought on it preventing filtration which is going to be very important in my case. I'll be doing a BB tank. So, no bio filtration from a sand bed. I'll also be going with minimal LR in the aquascapeing, but my rock panals should make up for that. As far as the nuisance algaes, should'nt we be takeing care of that by keeping low nutrients? Maybe we should start a new thread: The Great Coraline Debate.

Pito,

This is what you will need for a great BB tank. Keep detritus from collecting on the bottom with good flow. Get a great protein skimmer (no skilters, psyclone, or anything else that you know just can't produce).

Keep phosphate low (I run phospure from Drs Foster and smith). Phospure is equivalent to rowaphos (both are granulated beta ferric hydroxide).

The best lighting for a lot of coralline algae is probably actinics... for some reason, some coralline algae species love to grow in this type of light so I think that people trying to grow their coralline algae out should increase actinic light time and decrease the metal halide time.

Phosphate should be kept as low as possible as coralline algae does not do well with high phosphates or even moderate levels of phosphate.

Cheers,
John

 

[GuySmilie]

<a href=showthread.php?s=&postid=9201333#post9201333 target=_blank>Originally posted</a> by KyleP
I tried the 4 to 1 mixture of water softener salt to QuickWall Quickrete the other day and it did not work. Waaay to brittle. I'm going to try a 2 (salt), 1 (cement), 1 (sand) mix next time. The rock looked good though! Unfortunately it was nothing but holes. I think I can cut back on the salt and still have very porous rock.

The 2:1:1 ratio is what I planned to try, once the artic blast leaves our area. Keep us (me) posted on how the new ratio works for you!
Guy

 

[lildraken]

the 211 ratio

the 211 ratio

<a href=showthread.php?s=&postid=9209581#post9209581 target=_blank>Originally posted</a> by GuySmilie
The 2:1:1 ratio is what I planned to try, once the artic blast leaves our area. Keep us (me) posted on how the new ratio works for you!
Guy

i've done the 211 ratio and the rocks turned out great for me. Just remember not to mix in the salt until after you've mixed the water, cement, and sand. I used the entire bag of salt however because I buried the entire rock sculpture with salt until it completely dried so that the surface of the rock would be more porous. Once I let the concrete dry without burying the sculpture and it did not look as good as if you buried it.

 

[GuySmilie]

Re: the 211 ratio

Re: the 211 ratio

<a href=showthread.php?s=&postid=9210412#post9210412 target=_blank>Originally posted</a> by lildraken
I buried the entire rock sculpture with salt until it completely dried so that the surface of the rock would be more porous. Once I let the concrete dry without burying the sculpture and it did not look as good as if you buried it.

Yep, that's precisely the way I planned to go also. I was originally going to use a course grade of arragonite in my molding box, but that stuff is nowhere to be found in my locale.

So then I thought I could get the same surface texture using an irregular, medium-coarse grade of salt in the mold box instead of gravel. Brilliant minds think alike

I'm still concerned about the effect the salt leachant will have on the chemical composition of the finished product. Will just have to see, I suppose.
Guy

 

[Aqua Keepers]

<a href=showthread.php?s=&postid=9206238#post9206238 target=_blank>Originally posted</a> by rufio173
Pito,

This is what you will need for a great BB tank. Keep detritus from collecting on the bottom with good flow. Get a great protein skimmer (no skilters, psyclone, or anything else that you know just can't produce).

Keep phosphate low (I run phospure from Drs Foster and smith). Phospure is equivalent to rowaphos (both are granulated beta ferric hydroxide).

The best lighting for a lot of coralline algae is probably actinics... for some reason, some coralline algae species love to grow in this type of light so I think that people trying to grow their coralline algae out should increase actinic light time and decrease the metal halide time.

Phosphate should be kept as low as possible as coralline algae does not do well with high phosphates or even moderate levels of phosphate.

Cheers,
John

Yes, I been studying BB tanks for over a year and know what I need to do. My last reply was just stateing that I "think"
that coraline does clog up LR and slows its BIO filtration properties.

 

[lildraken]

Re: Re: the 211 ratio

Re: Re: the 211 ratio

<a href=showthread.php?s=&postid=9210646#post9210646 target=_blank>Originally posted</a> by GuySmilie
Yep, that's precisely the way I planned to go also. I was originally going to use a course grade of arragonite in my molding box, but that stuff is nowhere to be found in my locale.

So then I thought I could get the same surface texture using an irregular, medium-coarse grade of salt in the mold box instead of gravel. Brilliant minds think alike

I'm still concerned about the effect the salt leachant will have on the chemical composition of the finished product. Will just have to see, I suppose.
Guy

I just wanted to reiterate the importance of letting your rock sculpture harden in a humid environment for a week or two before you soak it in water. By then, the concrete will have hardened (hydrated) without dissolving the salt. Afterwards when you cure it in water, the salt should all leech out and you won't have to worry about it getting into the aquarium when it's done curing.

 

[GuySmilie]

Re: Re: Re: the 211 ratio

Re: Re: Re: the 211 ratio

<a href=showthread.php?s=&postid=9219029#post9219029 target=_blank>Originally posted</a> by lildraken
I just wanted to reiterate the importance of letting your rock sculpture harden in a humid environment for a week or two before you soak it in water. By then, the concrete will have hardened (hydrated) without dissolving the salt. Afterwards when you cure it in water, the salt should all leech out and you won't have to worry about it getting into the aquarium when it's done curing.

Thanks lildraken. Yes, from following several of the threads on RC, I surmised that a thorough 'damp' curing time was necessary. As for the salts leaching out, I'm not concerned so much about that as they are going to be placed in a new-construction saltwater tank anyway. I was more concerned with excessively elevated pH levels due to the ingredients of the cement itself. I know many folks have complained about very excessive time lines on getting the pH readings down to acceptable levels, once the 'wet curing' phase is started.
Guy

 

[ARIANNA]

This is an excellent thread and I have also made my own rock. My recipes varied and I believe it ended up somewhere around 2:1:1 give or take. My rocks were constructed in the middle of October and I agree that a week in the damp mold is a must before beginning the long soak in water. I soaked my rock for 2 full months before I got tired of going out in the cold to change water every day. I brought my rocks inside and put them in the 90 gal that will eventually be their permanent home. The pH was at 8.6 which I thought wasn't to bad. My attitude changed when 3 weeks later the pH was still 8.6. At this time I began adding vinegar to lower the pH daily. 6 gallons of vinegar and 2 weeks later I was looking for a better solution, so back to the thread I came for answers. Thats when I saw I could spead up the process by adding air. A maxi-jet w/venturi and two air stones made quick work of the pH dropping it down to 7.6 after about 10 days. I only had one problemm, calcium carbonate everywhere an eighth of an inch thick on everything. To top it off my water looked like milk. So I cleaned it all up and stopped the air. I'm now using vinegar again to try and get the last bit of calcium carbonate dissolved before I decide if I can add saltwater yet. What a pita, if it weren't for the great shapes and textures on my rock I think I would just throw it out and buy base rock. Anyway thanks to everyone who has added to this still growing volume.
Fred:strooper:

 

[lildraken]

Air bubbles naturally bring down the pH. I don't remember the details but something about adding more co2 to the water. when constructing your sculpture, you have to remember to make the walls as thin as possible without compromising the strength of your structure. the more dense your rock, the longer it takes the cement to hydrate. One of the caves I mad took 4 months to cure because it was so dense. I won't be make those again!

 

[Beenalongtime79]

Good luck Pito on the BB, I think you will pretty happy with the results!

 

[GuySmilie]

<a href=showthread.php?s=&postid=9221249#post9221249 target=_blank>Originally posted</a> by ARIANNA
This is an excellent thread and I have also made my own rock. .........

...... if it weren't for the great shapes and textures on my rock I think I would just throw it out and buy base rock
Fred:strooper:

I hear ya Arianna!
It really is a LOT of work just to save a few bucks. My incentive for all this is due to the poor choice of local rock available to me. It's almost a joke, especially at the price/lb the LFS are charging.

My only alternative is to have it shipped in and then it's WTSIWYG. And I don't like that option. So we roll our own.

Mr Wilson (here or on some other thread) was emphasizing that it is essential to spray down the cured rock with a diluted acid to restrict the precipitation of lime. I think he was fond of muriatic acid, IIRC.
Guy