The Ultimate DIY Rocks!

[Insane Reefer]

Fiji, Fiji, Fiji!
I think it is funny that based on a couple of articles written mainly for the company "Walt Smith" by Bob Fenner (and incorporated with the WetWeb site), Fiji rock has become "the rock". These articles are old - like 10 years old, but because they are still on the internet to be read, they are taken as gospel.

Remember - no real/published and proofed research has been done on true live rock, and which is truly the "best", as far as filtration is concerned. So anyone touting that "this one is better", is either trying to sell you something, or is giving you an opinion - and that opinion might be formed by someone trying to help a friend sell some rock, or from someone who read an article on the internet telling them which rock they should spend their money on.

I dislike Fiji Rock and so do a lot of folks. The LFS guy and I were talking, and of the last 350lbs he has gotten, it has all been balls (80%). Baseball to bigger than a basketball. Balls with holes, but it is still all balls. LFS guy has one rock he showed me, 7" radius (14" diameter), that weighs over 50lbs! This is porous? My 6ft long "Reef Face" (see gallery pics) only weighted 93lbs! And that was made with the Ol' Skool mix, plus a bit of salt.

There are several other types of true live rock that come in better shapes, are more porous, and have a much better selection of life. VANUATU, VAVA'U, SOLOMON ISLAND and MARSHALL ISLANDS rock all come to mind. A little more pricey, and sometimes harder to come by, but worth it, IMO.

But no matter whether you use true LR, or MMLR, you should always allow 1-2lbs of rock per gallon of capacity - this has been accepted as the correct amount for a moderately heavily loaded tank.

Ok, I'm done

[zachtos]

i have seen nothing other then fiji or baserock here in michigan, plus it's outrageously high priced, $7/lb is a deal here.

[Travis L. Stevens]

Good point Insane Reefer. While I tend to agree there is better LR out there, even though I prefer Fiji. It is quite simple that Fiji is the most common out there. Hence, this is why I'm going to do my test with Fiji.

PS I know that you weren't directing your comment toward my choice of rock for the experiment, but it related to it none the less I might be doing the test tonight, but I doubt it. Wish me luck

[Insane Reefer]

cmpenney, scanning through your other forum thread, you are using regular type III portland and, it sounds like you are planning the following?
2 days to dry/cure
A vinegar etching? for a day
2 more days to kure in freshwater

AND THEN IMMEDIATELY INTO YOUR SUMP?

You realize that the pH of that pillar is going to be 12-13 for the next 2 weeks at a minimum? Unless you are putting this in a system of several hundred gallons, you are really, really going to have to monitor pH and ALK.

I would seriously consider doing a proper kure for this rock, and not jump the gun...

[Insane Reefer]

You can get NICE rock shipped to even MI, for probably right on to what you are paying locally, Zach.

Travis. A LOT of LFS that I have recently visited (8 in the last month), have said the rock they had was Fiji, and it WAS NOT or was a mix of poor quality fiji, and other stuff. One place had FL aqua rock, caribbean, and some "other" nasty looking rock, all mixed up, and insisted it was ALL Premium Fiji, at $8.99 a pound. I actually laughed at those folks. I don't think they will be buying MMLR from me, lol.

I don't think Fiji is any more common than most other rock - I think most folks don't actually know what the different types look like, really, and so just accept that what they are told is fiji, is. You see it in tank pics all the time - "I have all fiji", and there is obviously some (or most) that is not fiji rock.
LFS people can read the internet too - and they see that everyone is "wanting" fiji, so that is what some of the unscrupulous LFS (or unknowledgable or gullible) will tell you they have. Often the LFS people don't know what they have gotten - so it isn't always the LFS, but the distributors who lead folks on.

Just based on what I have seen locally, here in MO, Maybe 50% of the rock being sold as Fiji Rock, actually IS fiji rock...
Maybe the average online is better, but I don't know.

[cmpenney]

I'm not planning on putting the tihin in my sump quite that quickly but I do have 2) 100 gallon sumps in my system not counting the rest of the system So one rock isn't going to through much off in the system.

Personally I could care less where the LR comes from there seem to be good and bad pieces from any location. I just pick through and find the good porous pieces and leave the thick solid pieces behind.

[dparson22]

why not use limestone. I understand it used to be reef rock way back when... I can get limestone for 20.00/ton. There is a guy here that uses it and had no problems at all.



I can't delete the copy posts can any one help?

[dparson22]

[dparson22]

[Insane Reefer]

Limestone is fine for a system, however, most limestone is too dense to perform any filtration (water has to be able to flow through the rock somewhat). If you are lucky, you might have an open pore type where you live, which would allow some filtration.
In the south, esp. Florida and the Keys, there is a lot of old reef limestone (often called coral rock) that hasn't really compressed - this is what places like Tampa Bay Saltwater use.

[toxqc]

ok so I'm planning a 180g and want to do a lot of DIY LR. In what department is located the rock salt ( water softener)?????

[Rhodophyta]

Originally posted by Insane Reefer
Limestone is fine for a system, however, most limestone is too dense to perform any filtration (water has to be able to flow through the rock somewhat). If you are lucky, you might have an open pore type where you live, which would allow some filtration.
In the south, esp. Florida and the Keys, there is a lot of old reef limestone (often called coral rock) that hasn't really compressed - this is what places like Tampa Bay Saltwater use.

There is a guy on Aquabid who sells this same Florida limestone.

http://www.aquabid.com/cgi-bin/aucti...er&Douglas6156

Florida Wildlife piles this kind of rock up for habitat in marine and freshwater locales. Looks like he found some up out of the water where he works.

[Insane Reefer]

I came upon this as I was surfing - I thought this might make interesting reading, esp. the bits on "concrete rock".

Interesting PDF

Notice page 8 in particular...

[blakeoe]

i use "texas holey rock" (honeycomb Limestone) In my tank for base rock before i put in the diy rock. It was fine. Just REALLY dense. It did however provide a good place for popds to breed.

[toxqc]

Originally posted by toxqc
In what department is located the rock salt ( water softener)?????

come on, you guys bought it, you must know were it was?

[ARIANNA]

It was by the front door in my home depot. Just tell the cashier how many bags you want and pick them up on the way out. Fred

[Rhodophyta]

Originally posted by toxqc
come on, you guys bought it, you must know were it was?

It is not available everywhere. The same chain stores in the county north of me don't carry any water softener salts. It may be or become illegal in some areas starting with California.

[Deuce67]

Originally posted by toxqc
come on, you guys bought it, you must know were it was?

Im not sure about Canada but at my local HomeDepot or Lowes, Its were the water purification section is at which is located where the kitchen displays are (counters and sinks).

[zachtos]

I picked up 640lbs of 99.5% pure rocksalt, 100lbs of sand, and 200lbs of cement to make a 3:0.5:1 -salt:sand:salt mixture. I plan to make as much as I can today.

**I'm unsure of how much water I need to use. Supposedly I mix the salt in AFTER the water has been added now?

[toxqc]

Originally posted by Deuce67
Im not sure about Canada but at my local HomeDepot or Lowes, Its were the water purification section is at which is located where the kitchen displays are (counters and sinks).

Thank you, I'll go and see if the HomeDepot here has it

[coryjac0b]

ok, so I've tried to read as much as i can so i can do a batch of large rocks for my new tank (210g). I have made some diy rocks in the past, they came out ok i guess. i used a mixture of crushed oyster shell, and Portland cement, used sand to mold them, let them harden for 2 days, then went through the curing process.

The going recipe that i can come up with is, 1:2:1 (Sand:Rock Salt: Portland Cement), is that right?, And most people are using the rock salt to mold them?

[Insane Reefer]

Originally posted by toxqc
come on, you guys bought it, you must know were it was?

You can get it in most grocery stores, usually in the isle that has laundry/cleaning products, or the isle that has charcoal - I have found it at every local grocery, for the same price as HD or Lowes. Wal-Mart also carries it, usually in the area that has things like AC air filters, dehumidifiers, etc. - they carry Morton brand, and is usually 50 cents cheaper a bag.

HTH

[Insane Reefer]

WARNING - LONG POST!

Hey All,
I'm going to post my favorite tips and links every so often so new people can find it all pretty easy. It is a summation of the most commonly asked questions and things I have picked up through making my batches. Some I’ve gleaned from this thread, others I’ve learned from past mistakes and experiments. I've been making DIY man-made rock or aragocrete off and on for close to 8 years. Lately, I have even made some money on my rocks

I thought I’d pass this info on – maybe save someone some frustration or spark a new idea.

I will continue to refine and update this post as more info is added.



First, good info can be found at these two places - I think everyone who wants to make rock should read these in full. One of the articles gets pretty heavy handed with the science/chemistry aspect, the other babbles on tangents once in a while, but both are worth the read, IMO.
ARAGOCRETE RESEARCH BY TRACY GRAY
Reef Propagation Project:

And this link is for Cement Colorant – I’ve spoken with the vendor and am assured that, given our kure process, this stuff will be safe and colorfast in the aquarium. They sell it in small amounts in rainbow colors and are very cheap.

List of Aggregates
Sand - caribbean/aragonite is best, but very hard to find. Toys R Us carries a play sand that a lot of folks use and report no trouble with. Limestone sand has gotten good results as a DSB, so should also work.
Crushed Coral - AKA "CC". Makes nice, realistic rock, but expensive
Crushed Oyster Shell - AKA "OS". Any shell will work, but OS is very cheap at feed stores.
Salt - Many thanks to Travis Stevens for figuring this out! The salt of choice is "Solar Salt Crystals", typically found as a Water Softener Salt. 99% pure salt. Get the coarsest crystals you can find. Solar Cube can be used, but is sort of chunky - makes nice holes though. Boiling the "cubes" rounds off the edges and makes nicer holes. Solar Pellets can also be used, same as Cubes.

Rock Recipes
Ingredients are measured by volume, not weight!

Original Recipe: 4:1 - 3:1 / Salt:Cement
Improved Recipe: 3:1 - 2:1 / Salt:Cement
Ol' Skool Recipe + : 1: 1.5 : 1.5 :1 / Salt:Cement:CC&OS:Sand

Molding Material
Really, pretty much anything that is dry and crumbly will work. I've even used stuffing bread crumbles, but that draws bugs while it dries.

Soil
Salt
Sand
Clay

A certain portion of the molding material will remain on the rocks - this can usually be removed with a short acid bath, followed by a good scrubbing with a plastic or fine wire, bristle brush.

If you use Rubbermaid or Tupperware, you can reuse molding material over and over again. Line cardboard boxes with plastic to prevent moisture leak and wall collapse.

DO NOT Wet Salt, if it is used as a mold material - this means when working with salt, do not add water to the casting box as you would or might with say clay or sand.

----------------------------------------------------------------
Now, I will list my tips and tricks, in no particular order. Many will seem stupid or like common sense, but you don’t know about some people’s kids, lol…

Tips and tricks

1. Wear gloves when making rock. If possible, don’t let the cement get on your skin, especially the dry powder. If possible, wear a painter’s mask when measuring and mixing dry cement; this stuff can really burn the inside of your nose.
2. Setup your work area in advance; cover surfaces with plastic or old sheets if needed (like in your kitchen or living room). Fill casting containers with whatever mold material you are using, or have it standing by within easy reach. Give yourself walkways if you are making a lot of rock – nothing sucks as much as trying to create enough work space after the fact.
3. Think about the weather for not only the day you cast, but the next few days as well, if you plan on doing this outside. Rain can make a mess of things…
4. Use Portland Type I, II (I/II) or III – these are known to be safe for use and make rock with proper porosity.
5. Mix all aggregates excepting salt into the cement before adding water. Add salt after you have reached the right wet consistency, and mix it in lightly – the less salt is leeched off the grains of salt, the stronger your final rocks will be. Water softener salt of the type “Solar Salt Crystals” works wonderfully (Thank you Travis Stevens!).
6. I prefer to use crushed coral and sand in my rocks for long term strength, plus salt to add porosity. The aggregates also give realistic details to the rock. My preferred recipe is 1.5 part cement + 1.5 part sand + 1 part crushed coral/shell mix + 1 part salt, but this is expensive to make. You can also use a mix of 1-1.5 cement + 1-2 crushed oyster shells + 1-2 salt.
Mainly, a 1 part cement to 3-4 parts “other” is acceptable, whatever you want to mix together is up to you and you should be ok if you follow the 1:3-4 part rule.
7. Work in layers for added dimension. If you lay a layer of molding stuff in your container, make a few divots in this molding layer first, and add cement to these first to make lumps on the bottom, you can avoid flat bottomed rocks. Now lay the main part of your rock, adding molding material as needed.
8. You can make neat “cliff-face” striations if you take a handful of salt, and lay it just along the top edge of wet cement, forming a narrow line of salt along the edge, laying a thin layer of cement over the salt, and repeating this to form, on the outer edge of your rock, a sort of cliff that looks to be cut by water action.
9. Anything cast thinner than an inch is likely to break, unless you are careful with it.
10. Find a nice bit of stainless steel or aluminum wire – 2mm or so in width, and bend a handle for one end (remember you will probably be wearing gloves, so bend accordingly). As you cast your rock, use this wire to poke Lots of little tunnels all through the rock – all the way through if you can; this will make the rocks extra porous, and give bug life lots of places to hide and propagate in-tank, as well as allowing more water to move through the rock. Alternatively, you can cast the piece, and then poke as much of it as you can – though this way tends to look a bit contrived. I like the first way better.
11. Once your rock has cured and it has been curing for about a week and if you made it mixed with stuff like crushed coral or shells, mix up a weak acid mix and scrub the outside of your rocks with a stiff bristle brush. Be sure to take proper precautions when working with acid – not only from burns, but from fumes as well!!! If you only made your rock with salt and cement, ignore the acid wash, as your rocks will dissolve, but still give them a vigorous scrubbing - this will loosen the weakest stuff and get rid of it without shedding it all over your tank. If you have shells or coral, this can make the surface even more porous, and clean cement films from shells and the like that might be on the surface. I use a mixture of 1/2c muriatic acid added to 2c water.
12. You can make “lock together” pieces by wrapping a bit of PVC in something like tissue paper or plastic wrap, sticking it in the wet cement of “part a”, and then laying plastic wrap over and around the fresh cement/PVC, and then cast “part b”, making sure to get a good fit around the PVC join. I find this works, but I personally have an easier time if I cast “part a” with PVC set into it, let it cure, then wrap it well with whatever, and cast “part b”, and I can cast really large pieces this way.
13. “Cement Paint”. You can make up a slurry of cement and sand, say 1 part cement to 2 or 3 parts sand, made fairly thin and fairly wet and sloppy, and use it to decorate rock with “coralline algae”. I use white Portland, but I don’t see why white grout or mortar wouldn’t work as well. You can use cement colorants to color the cement any shade you desire. Working with a paintbrush, you can easily replicate the swirling patterns of coralline. I’ve also used this mix to paint/dry brush grey Portland rocks to white.
14. Branching rock/Coral skeletons. Pick PVC pipe a bit thinner than what you want your final piece to be. Cut into appropriate lengths, cutting one end flat and the other at an angle. Drill plenty of holes in the PVC to help the cement stick on. Drill extra holes on the very end that will allow you to tie the pieces onto the “main branch” with zip ties. You can bend PVC into believable shapes using heat from either a propane torch or a heat gun, and a couple of pairs of pliers (use appropriate precautions). After you have your PVC framework, mix a thicker blend of Cement Paint (less water, more cement) and paint/dip the skeleton, covering completely. I recommend hanging to dry, and dipping several times, using a paintbrush to smooth it out and prevent weird drips. When done coating, tie a grocery bag around the hanging piece to preserve moisture and allow to cure 48 hours or more.
15. Think about how corals come to you, as frags and whole colonies, and think about how hard it can be to attach these in your typical rock pile. Flatter surfaces and shallow bowls in larger rock shapes can make latter placement easier.
16. You can make rock “shells” if you want to avoid the rock pile look altogether and these are only limited to your imagination and size constraints. You can stuff the cavity in the back of this hollow construction with cheap $1.99/lbs rock, or whatever you want. I DO NOT recommend making these with the cement and salt only recipe! Make a form of some sort (use your imagination), put it in a box that will fit into your tank (making a rock too big for the target tank blows), and secure it to one side, or more (for multi-part casts) with duct tape. Line rest of box with plastic. I made my form from plastic grocery bags stuffed into a garbage bag, with a little air added, and taped that into the target box. Slowly build the shell wall (adding details as you wish), filling the box with salt/molding material, until you have the form covered with a fairly uniform covering of cement. LEAVE ALONE FOR A WEEK! Cover with plastic if you can.
17. Frag Plugs. If you have extra cement at the end of the day, make frag plugs by using a mini muffin pan, and filling with ½in. of cement. Spray the pan with cooking spray for easier release. These can be put in a mesh bag and cured in the toilet tank.
18. Hate scraping the back wall of your tank? You can make thin wall covering sheets that can be glued with silicone to the back wall of your tank. Alternatively you could make shelves along those lines. I find casting on a sheet of glass covered in plastic works best for this. Also marking out the actual measurements of the back wall onto the glass helps to avoid sizing issues. I DO NOT recommend using the salt and cement only recipes for this application, nor the use of any salt at all! I also mix this just a little wetter than I normally use. Once you are setup, just drool the cement onto the covered glass. I tried doing large sheets, but these mostly were too weak to hold up. I find making smaller pieces (12inX12in or so) that abut like a puzzle work best, and sort of give the illusion of looking at a cracked and crevassed reef wall. After you cast these, they need to be kept moist and unmoved for 3 days. Believe me. They do. And you will need to mist them once a day. I just covered mine with a garbage bag and used a water bottle to mist it. I recommend an acid wash, as described above, once these have kured for a week.
19. If you make a rock or rocks you don't like, either use fresh cement mix to add some new bits, or break the rock up and use it as aggregate in your next batch - no waste is good
20. The moister you can keep the cement while it cures, the harder the final rock will be - try wrapping it in a bag, or misting it while it cures. Supposedly, if you can let it sit for two weeks before starting to kure, it will dramatically speed the kure time.
21. Dust your molding sand with oat flour for easy removal of surface sand. Thanks Rhody!
22. Mix molasses with your molding sand to give it more texture. Thanks Rhody!

Various things I have used and have worked for me for adding details:
1. Cemented Nylon String. Makes realistic tube worm/duster tubes. Make a thin paste of just cement, and dip small lengths of the sting in. Wipe excess off between fingers and lay onto the rock in desired figure.
2. Veggie Capsules. These can make little tunnels when laid end to end in the wet cement, and then covered with more cement. Or poke into outside edges to mimic polyp holes. Do NOT mix into the cement mix.
3. Nori Sheets. These can be wetted and formed into shapes or rolled into tunnels.
4. Balloons. Both the round and “animal” ones work. I find that filling them with water makes them stronger. Doubling them up works well too. Make sure that you can get the balloon out afterward - i.e. leave the knot sticking out.
5. Cardboard Rolls. Can be cut to form bracing, tunnels or for pillar shapes. Be sure to use it in such a way as will allow you to remove it after a few days of kuring. Hemostats work great for grabbing a-hold and pulling it out.
6. Tissue Paper. The white stuff you find in gift bags. Disintegrates quickly during kure. You can make little (or big) “salt bags”, that you can lay into the middle of larger rocks to give more holes for ‘pods and the like. Can be used to make caves and tunnels. Just use a small bit of paper, lay some salt in it and twist or tuck the ends – a small bit of cotton thread could be used to secure the package too.
7. Pasta. Must be cooked “Al Dente” before use. Do not mix into cement, it only makes a mess and is a pain to get out of the rock as it gets really hard and crunchy when the rock dries (ever scraped 3 day old pasta off a plate?). Use to add spaces in the rock, or tunnels with spaghetti (at your own risk). Rigatoni adds a nice effect if placed just right.

Things that DO NOT work:
1. Vinegar/acid kuring. Waste of time. Lowers initial pH, but pH will then later spike.
2. Bio-degradable packing peanuts/Cheesy-poofs. I can find no way to really use these that is also safe for the tank.
3. Fish food pellets. That was really, really nasty. I don’t want to go there.
4. Uncooked Pasta. As pasta absorbs water, it expands, causing the cement to fracture and crack – cook it al dente if you really want to use it.
5. Alka-Seltzer . Doesn’t work. It dissolves to quickly.
6. Yeast. Doesn't work. pH kills the cells before they can respirate. Though during the Kure, this might be a speed option.


Rock Kuring
Kuring your rock is the next hurdle. It is really, really best to leave your rock alone for at least a week before starting this step. According to Quikcrete reps, it takes 7-14 days for the rock to stop curing/hardening (though this process is actually going on for a lot, lot longer) - even though it looks and feels done. By putting your rock in the kure bin too soon, you are wasting a lot of water and making weaker rock. Rocks during this 2 week period will naturally loose pH - from 12-13 at casting time down to 9-10, with NO WATER USED. I theorize that rock left longer, like 8 weeks, will only need a few weeks of kure time (and lots less water!).

Kuring is pretty straight forward. Lots of time, and lots of water changes with adequate water volume, unless you have access to a reasonably clean waterway. Powerheads help force water through the rock and help the insides kure out. Pumping air via a stone, or using a CO2 contraption (or sugar and yeast) supposedly makes the rock kure faster, harder and better. When your bucket kured rock quits leeching out white scum on the surface of the water, and stops leaving a white residue on the bottom of the bucket, you can start checking for pH. Rock has been known to kure in as little as 2 weeks, but most bucket kured rock takes 6-8 weeks to reach safe levels – some will take up to 3 months. Be prepared to wait.

To properly test for pH, change the water – either use RO/DI or aged saltwater. Let the rock sit in this for 4 days without air or powerheads – you want still, stagnant water for this. After the 4 days, give the water a bit of a stirring and check pH with appropriate test kit. If it is in the acceptable range of 8.0 to 8.6, it is probably safe to use. If not, continue to kure.

If adding your rock to a newly established tank, you can go ahead and put it all in at once. If the tank is older, with inhabitants, you may wish to only add a rock or two at a time, to allow the system to “settle” between each addition.

Expect an algae bloom.
A few people, those who either have waterways to kure in, or those with really butch systems have reported no algae blooms, but I suspect they are the exception, not the rule. If your tank blooms, don’t panic. Most tanks bloom within the maturation period anyway. Double check your system for things like NO2 and NO3, and other algae causing symptoms and correct anything that isn’t up to snuff. Take all the normal steps to curtail the growth, but then just ride it out. If the bloom is caused by the rocks, the algae will soon deplete the readily available nutrients and starve itself out. If it doesn’t go away within a few months, then you should check into other reasons for the bloom.

Well, I think that about covers my repertoire. I apologize for the length of this post, but hopefully some of you will find something of use…

I encourage the rest of you to take some time to write up your experiences and tips and share them with us – by sharing our experiences, we all learn and get better and better at making our own rock.

Good Luck, and Rock On!

[thriceanangel]

Wow, impressive! That pretty much says it all! Almost no need for the thread now!

[Afishianado]

Thanks for that last post. I found it very helpful. I have been going through the discovery period on DIY rock for a couple of weeks after reading this thread when it was younger. This synopsis helps to clarifu a few things.

Has anyone used regular table salt as a form material? I just don't like the surface texture that gets left by the Solar salt. I tried the table salt thing the other day only to realize immediately after starting that I grabbed the 10lb bag of sugar instead of the 10lb bag of salt. The grain size of the sugar was a dream to work with when forming and the surface texture left behind was beautiful, but I took it out of the mold too quickly(about 20 hours) just to see how it was progressing, it ended up being a mess but I still have some chunks dry curing, we'll see how it goes.

I read that PDF about aquaculture and the concrete/styrofoam rocks they used as part of the study. I was discouraged though to read the report in it's entirety and find that concrete had far lower coraline algae growth than the other substrates