DIY Live Rock - by Ed

This is a video about how I make DIY rocks for my aquarium. Basically you use three ingredients: 3 parts crushed oyster shells, 1 part white portland cement #1-2, and 2 parts rock salt. Mix and mold. Cure the cement in cold water. Then to make it live, cycle it with a live rock from a friends aquarium of the local fish store.
To make sure the rocks don't fall apart the water to cement ratio (weight ratio) should be about 1 part water, 2 parts cement. Too much water severely weakens the cement.
Before putting the rock in an established tank, test the pH of the water the cement has been curing in to make sure that the rock won't raise the pH of your system. The pH of the curing water should have a salinity at of very near 0 (SG of 1), and the pH should be no higher than the pH of your tank, but preferably lower.

[@supersaltwaterfish]

omgosh. The salt makes it Pourus with holes everywhere, thats why he rinses for a week. The salt breaks down on the inside and makes a ton of nooks and crannys for homes. Dude this is awesome!!!

[@waynewayne9693]

That’s common sense. WTF did you think was going to happen to the rock salt?-

[@aeropostalbaby1]

@eddiekern ive watched at least dozen of these videos and read about a dozen more forums. youre the only one who has explained the entire process, prices, location of buying the products, and successfully produced a good quality porous rock as a result. this is by far the best diy live rock demonstration on the web. thank you very much my friend

[@danielbui23]

Ed, you are doing a great job and because of you alot of people are benefiting by making their own base rock. When you get a chance make a video with your DIY rock and show everyone the benefits.

[@phil47952]

eddiekern, Your video is by far the best one I've seen on making reef rock, thank you very much. I've been thinking of doing this for a long while and you've convinced me to try. Phil

[@OceanproAquatics]

Looks better then the rock we made when you worked here dog! Great job. I like how poreous you got the rock to be with the rock salt. You were right not to use the silica sand also otherwise it fertilizes nusance algae. Looking forward to seeing it after a month or so when it coralines up! Great job Ed. Michael

[@acanskywalker5631]

Thanks for this awesome live rock recipe/tutorial! I'm going to buy a large plastic children's pool tomorrow for creating my molds along with all the other ingredients so I can get started making a few hundred pounds for my next build!

[@eddiekern]

For large holes I would recommend making two rocks, one with a cavity on the bottom and another with a cavity on the top using the sand mold process. For smaller holes I have heard of people Making "rock salt lumps". I would do it by dunking a handfull of rock salt in water, and putting the dampend salt into a bowl with a paper towel under it, and letting it dry. If you put that ball in the prepared mix when you put it in the mold, you should get a pretty cool cave.

[@nick360700]

excellent video!!! 100% great and informative....hope you will continue to make and upload more videos of your rock and aquarium startup process!! youtube is defiantly a better place with you here!!

[@Forgetii]

Great video. I've seen several other artificial live rock videos, but yours seems to break down the process to a more manageable level. I've several of your other videos and thoroughly enjoyed them as well.

[@mstinkagain]

Thanks for the suggestion Ed. I did mix the salt in last but I will use less salt and more cement and get back to you with the results.

[@mstinkagain]

Hi Eddie, I thought my live rock wasn't holding together but I let it sit longer and it seems that the inside of the rock is fine but the outside crumbled away. So it is actually working. I think I will add a little more cement though next time. Thanks for a wonderful informative video!

[@rogie75]

Cheers Ed, will do. Thanks for the advice, looking forward to more videos.

[@AerosolRenegade]

Great video man that rock looks A+!!

[@eddiekern]

@BobaJett Give me some background on the tank. Is it just being established, has it been around for a while? Is there anything in it yet? What kind of bottom substrate are you using? What kind of filtration do you have? I still think it is likely silt and clay that is not settling out. If that is the case, water changes would be best. Or if there is nothing in the tank yet, you could let the water sit still for a few day, that will allow the small particles to settle out.

[@eddiekern]

@BobaJett The milky white stuff is fine particles in the pool sand (cacium based silt and clay). If the water has heavy circulation they won't settle out since the settling velocity is so slow. Is the water your working with fresh or salt?

[@eddiekern]

@hollabacknow8557 (Part 2) - When you cure the cement you want to do that in freshwater. When you cure the live rock you want to do that in salt water. So ... You want to let the cement harden and rock salt dissolve in fresh water and you want to let good stuff grow oin your rock in salt water. So when you you go to "cure the live rock" you can do that in your new salt water tank. (the whole curing confusion is because the English language uses the same word for both processes)

[@eddiekern]

Okay, a lot of people seem to be having the same problem: The rocks being frigile and falling apart. The solution is actually quite simple. Less water ... the cement to water ratio should be about 1 part water to 2 parts cement. Now that does NOT take into accout the water that gets sucked up into the oyster shells. If too much water is added it severly diminishes the strength of the cured cement. So less is more when it comes to the water (so long as there is enough to hydrate the cemet)

[@eddiekern]

I would add more cement, and maybe consider cutting bacok on the rock salt. When you mix it, be sure to mix the cement, water and substrate first, then at the very last moment, add and mix the rock salt (mixing just enough to distribute the salt through the mixture). That should do the trick. Let us know how it goes.

[@eddiekern]

@hollabacknow8557 I used Type I/II. Type II cement is moderately sulfate resistant, and since it will be in a salt water tank you want sulfate resistance, so make sure the cement is type I/II, type II, or Type V (high sulfate resistance). As you have probably figured out the color doesn't really matter.

[@YoutubeFella]

thanks ed, followed your video and ended up with some great pieces!

[@eddiekern]

Okay, so if your having trouble with the rock holding together there's a few things I would recommend. 1) add some of the pool sand into the mix; it will strengthen it 2) more cement 3) less salt 4) be sure to let it cure while moist. The sand that you shape the rocks in should be moist, then you should put them in the curing (referring to the cement curing, not the live rock) bucket after about 24 hours. It you let them dry out in the first day they will be a bit more brittle.

[@eddiekern]

I sure do. You want water flow to help dissolve as much of the rock salt as possible in the shortest amount of time. I'm cheap so I do it with airstones. A better way would be a powerhead, but he airstones work just fine.

[@ukeka]

Kool Idea ... I think I am gonna try this !!!

[@stijn2385]

Hey Ed, Do you have an aquarium at the moment? If so how does this rock look like in your tank? Would you recommend making this over buying dead rock? Thanks!

[@flyingSnakess]

fine shell grit is good also, i add some crushed coral sand to the mix aswell..

[@BobaJett]

I had one batch do the same Lova. They just fell apart. That particular batch I crused up my salt pellets and I think that was the mistake. Try adding less salt & make sure its very coarse & not powdery. try adding a bit more cement as well.

[@folkiethirteen]

Great vid. just what I was searching for. As a means to soak and rinse the rocks could you not put pieces that will fit into the tank portion of your toilet then every time someone flushes fresh water rinses away the salt and other things like the cement leaching as it cures?

[@chris3141084]

Your local "feed store" will have it, its typically given to chickens to have stronger eggs. Like he said it comes in 50 pound bags for around 10 dollars.

[@eddiekern]

That would work just fine, it is all a matter of preference. Personally I would probably add a little bit more cement in the next batch I make. I would probably increse the ratio of cemet by about 20%

[@UstadZed]

this is really cool.. thanks for the idea. perhaps i will try it one day when i need lots and lots of rocks.

[@BobaJett]

@eddiekern Its fresh water. I let the rocks cure for several weeks in water, then I let them sit in the sun for a few days as well. I thought the filtration would clean up the water, but it hasnt.

[@eddiekern]

@electronkid710 I would shy away from rock melting salt because sometimes they use chemicals in it. If there are any livestock supply stores, they should be a safe bet.

[@spankythepyro]

You have to watch though because when doing this for a large display you will be holding up all the rock above it as well. The Oyster shells and portland should be enough, for a less shelly surface mix in some medium or large grain sand as well. The Oyster shell rock is light enough and porous enough to mimic live rock while still maintaining structural integrity.

[@KevinBlakely]

Hey Ed. Great idea using the rock salt. I would like to attempt to make an entire wall (for the sides of a 92 gallon corner). See any reason why this wouldn't work (other than weight). Each wall would be about 24" x 32". I also would like to embed some PVC pipe in it, for current. Do you think it would hold together long enough to get it in the tank or will it need some reinforcement? If anyone has an thoughts I would love to hear them.

[@Okiimiru]

This is an incredible technique because the rock you made is so porous. How is your copepod population? Do all the little holes inside the rock help more copepods live in it?

[@eddiekern]

Sorry it has been so long since I have posted a comment, school, work, and junk has kept me pretty busy. so bad news ... my landlord put a stop to all my aquarium related activities. So for I won;t be able to turn the base rock live for a while. But PLEASE keep posting to let me know how things are going and to suggest any improvements.

[@eddiekern]

@hollabacknow8557 It is not needed, and it is expensive where I live. If you want to add calcium based sand then it will help a bit with adhesion. But it is not needed if you mix the cement carefully with a ratio of 1 part cement, about 0.4 - 0.5 parts water.

[@supersaltwaterfish]

but doesn't the rock salt make it porous which is really good. I'm guessing a tons of small shells would work maybe.

[@eddiekern]

The big salt is probably the same as rock salt here in the US. just make sure that each grain is about 2-5mm in diameter. I'm working on turning the dead rock into live rock right now, when I'm through with that I'll post the video.

[@Teslastorymma]

nice process. great video. kudos man. very insightful

[@icecoldcola08]

What i found funny was, your rocks jumped from the black tub to the blue tub within them 12 hours! xD

[@ltkenbo]

@Arteolike I know people have successfully used rite dye (fabric) however with no problems. Most cement dyes are terracotta based so it would probably be ok.

[@eddiekern]

I actually test with an electronic pH probe, but the salinity of the water needs to be close to zero before we can consider removing the rock. Ideally all the salt that the water can get to should be dissolved before removing the rock from the bath. So the short answer is freshwater

[@moneymarkj]

Pretty nice...Do you experience any algae growth or any bad things once the rock is in the tank?

[@eddiekern]

Yes admittedly the salt is bad for the cement. Ultimately this will not matter because all the rock really has to do is support its own weight underwater. So what would you recommend instead?

[@1babelove]

Ed, when you are doing the PH water testing are you doing it with the fresh water or salt water kit? I ask being that rock salt was involved in the mixture and will leach into the water with the lime from the cement.

[@frankkarma]

great video. thanks for making it and posting.

[@TheIceDragon]

Would be awesome to see an update video from a tank running these rocks for a while! I try searching the internet for diy live rock covered in coraline, but cant seem to find any :/ Does this suggest that DIY live rock isn't that good in the long run?

[@eddiekern]

@Arteolike I don't know what they use to make cement dye, but I personally would shy away from using dye.

[@gpro76rmp]

Thanks for the great video. I just have one question about the white pool sand you used. Can you use it as your live sand in aquariums?

[@iLLaPiNo83]

Nice! Is there any specific type of pool sand i have to buy?

[@eddiekern]

@gtileo Just make sure there are no chemicals in it, and it can be really hard to tell. All I know is that a lot of "ice melt" salt tends to have chemicals in it.

[@Arteolike]

Can i use a cement dye? I am planning on leaning outside in a tub water for like 3-5 months... then cure it in saltwater for like 2 -3 months.

[@eddiekern]

I have no idea. I would be inclined to suggest food coloring, but even then reef critters could be sensitive to it. All-in-all I would be inclined no ti use dye.

[@eddiekern]

It can be made without the salt, but what the salt does is make it porous so that the rock has a lot more surface area for micro-flora that breaks down fish poo. Also it offers a place for pods to go and not get eaten by the fish. If you do not use salt the water will not pass through the rock like shown in the video, it will run over the surface instead. @rogie75

[@nick360700]

Hi, I live in London and i have been searching for rock salt but i cant find any. i just wanted to know what it is usually used for? is it the salt that you use to melt snow?

[@mstinkagain]

I made this with aragonite in large pieces, portland cement and rock salt in the same amounts you have listed. Unfortunately, it didn't hold together. It falls apart. I think I need to add more cement. What is your opinion?

[@TikiTak321]

What is the point of covering up the cement with sand after you put it in the sand mould?

[@eddiekern]

The rock is plenty porous for the rock salt to disolve. Esp if you let it cure for 4+ weeks. Besides, even if and oz of rock salt disolved in your tank 1) it would disolve very slowly ... like rock salt. 2) Salt would assumulate more quicly on the side of the sump than any disolving rock salt.

[@glennbarnett8866]

Thanks for the video and recipe!

[@BobaJett]

Im a bit confused. You say dont mix the rock salt, but yet you have to, to a point. Do you just add it, stir a few times and pour? Also, My last batch I used the rock salt and the next after overnite curing, the rocks fell apart in my hands. In your experience, is that too much salt/mixing, or not enough cement, or what?? Ive had plenty of non salt rocks turn out perfect, but I wanna reduce weight and have the porous rock as well.

[@dylandabomb230]

did you change only like 1/2 the water or all of the water when you change it

[@rogie75]

Ed, just out of curiosity...can it be made without the rock salt and what is the purpose of it? Thanks

[@Mixbag]

will this rock be safe in a freshwater setup ? and after i make the rocks i leave them in water for one month then there safe to use in your fish tank ? can i use normal cement ? as im not botherd about colour

[@Lancero1013]

Actually, i ran across something I thought might work. Instead of rock salt, I got a 50lb bag of rock salt pellets. Theyre about the size of marbles. Im gonna give it a try and see how they turn out.

[@Lancero1013]

Is there another matreial you could use to create larger holes? I want to create rocks for Cichlids since holey rock is so damn expensive.

[@Arteolike]

@ltkenbo I think ill stick with white Portland cement. Hey everybody, remember to use sand WITHOUT SILICATE, or you'll have HUGE air algae problems. Silicate is the shiny stuff on your hands after you pick up some sand, if the sand has that... DONT USE IT, form your rocks in ROCK SALT Also, Wash the Crushed oyster shell, it will make the rocks "whiter" and reduce ammonia.

[@eddiekern]

The rock is somewhat fragile. Its not going to break on its own, but a drop from 1 meter would probably break some of the larger pieces.

[@BobaJett]

@eddiekern Hey, I was wondering if any of your tanks with this rock in it have a milky white wahue to the water? I just cant get the water to clear up.

[@1aPPro]

I NEED HELP lol. I am using type 1 white portland cement, play sand in the box,extra course water softener salt, and crushed coral and something else I forget the name but its a mixture of shells because I cant find oyster shell anywhere.I have tried several times but nothing comes out like yours.Its winter in texas but has only been getting down to the 40's(dont know if this effects anything).I let my rock sit for 24 hrs and it still crumbles. I have no idea what im doing wrong. please help.

[@eddiekern]

An animal feed store. They are fed to chickens to make the egg shells hard. @Matheis93

[@eddiekern]

The crushed oyster shells are fed to chickens as a cheap calcium supplement. I found mine at an animal feed store. I don't have the brand name of the ones I bought.

[@electronkid710]

wait the salinity should be 0? what if i have a saltwater tank should i use the saltwater parameters?

[@eddiekern]

The rock salt here in the US is used to melt snow.

[@eddiekern]

@xen552 Because even white cement is pretty grey when it is wet.

[@acidlittle]

A good way to semi-cure the rock is to put it in the back part of your toilet (the reservoir part) should help flush out the rock salt with each flush, put it back there for a month or so then put it in a tub with salt water for another 2 weeks and when the PH is safe throw it in the tank

[@franklinmichael671]

How do you cure the cement to stop it from raizing your pH? Just letting it sit fixes the problem?

[@eddiekern]

Hahaha sorry, I work in tech support so sometimes I just assume the worst. I would play around a little more with the amount of water, and be sure to add the rock salt last, after eveything else has been mixed thoroughly. After you add the rock salt mix it as little as possible. Maybe even add less water and see what happens. Or maybe your rock salt is dissolving too quickly. All could be factors.

[@eddiekern]

I'm not really sure what solar salt is, but I played it safe and got my salt at the animal feed store because I know that it was chemical free.

[@eddiekern]

@spunkbobstainpants Once the cement cures, and the salinity zeros out, I would introduce the rock into your mature tank a few kilos at a time. If you have a mature tank you may as well just seed it there. I would introduce a small piece first, and wait a week or two to ensure that all your critters stay happy and that the new rock doesn't upset them, then I would introduce it at a rate of about 3 kilos per month just to stay on the safe side.

[@erichott223]

Why do you have to use the rock salt? Can you just use the other two and make this work?

[@eddiekern]

@GRRjammm The salt makes the rock porous. Without the salt these would not have as much surface area for poo-eating bacteria to grow ... and they probably wouldn't look as cool either. I wish I could tell you how it looks in a tank, but my landlord stopped the progress on my tank, so I still have the rocks, but no tank to put them in :(

[@Arteolike]

@early1991baby I don't know. I had a freshwater aquarium, added sand that contained silica i had HUGE algae within a week, a month later cleaned it 100% Used gravel instead of the sand, no algae to this day.

[@TheMRhamad]

Rock salt : is it the same one they use for cooking ?

[@eddiekern]

The pH of 7.6 should be fine. All the calcium in the rock is actually buffering the pH. Its odd that your tap is slightly acidic. But 7.6 is fine. Rock salt in to make the rock more porous so that more micro floura can grow within the rock.

[@electronkid710]

i cant find rock salt anywhere. all i can get is like the ice melting salt. is that ok or is there any online source for it.

[@eddiekern]

Maybe, you'll have to try it and let us know how it goes. I suspect that they will be okay, but the rock wont be anywhere near as porous as the rock salt. But I've never tried it so I don't really know.

[@eddiekern]

It can house bactaria. Just be sure to seed it, which is somthing I don't cover in the video :) @xbk62x

[@mstinkagain]

Unfortunately, my second batch fell apart. I think I need to add even more cement. Or let it harden longer. I let it harden 24 hours but my sand was pretty moist.

[@eddiekern]

I was planning on it. That being said you would need to clean it, which will probably take many many hours.

[@eddiekern]

If you can't find rock salt then I would recommend not using the salt at all. If you can't find a pure salt that is about 3-4mm in diameter or larger then I personally think that your better off not using the salt at all. Fine grain salt is not going to offer much benefit as far as porosity. If you read some of the comments for this video, some people have had some good ideas for alternatives to the rock salt.

[@fryedrice945]

why is it good for the rock to be porous?

[@CameraMan7410]

hey bro, ive made some diy rocks, and im in the curing process right now, and i tested for pH, but they dont match. its been curing for around 5-6 weeks now. the ph isnt even remotely close to each other. my tap is around 6.4-6.6, and my rocks water is around 7.6. is there a possibility that the ph is so high becuase i have a powerhead in there, and it aggitates the surface? please let me know...

[@eddiekern]

@hollabacknow8557 You want to cure the rock in fresh water. And you want to change the water out regularly until the salt content in the water evens out, or goes to zero. Also "curing the rock" can mean two things. 1) curing cement - letting the cement harden. (which is very alkaline) 2) curing live rock - Letting good bacteria grow on it. You need to "cure the cement" (and dissolve the salt) before you should "cure the live rock".

[@johny2422]

So once i my rock has cured from the cement..(0 ph ) can i go ahead and drop it in my tank and let it seed in there??

[@eddiekern]

Then keep curing the rock and doing water changes. The ph will be off and the salt will be high while the rock is curing. Probably for at least a week or so, or even longer depending on how often you change the water. @lilalancarey

[@christopherfaison5442]

Have you had any issues with your rock crumbling over the years?

[@dylandabomb230]

what does the rock salt do

[@aleixcutillerserra6410]

Well... i have a question and a problem... i did those rocks with white cement, coral sand and, dead coral, and some salt BUUT... the place where i did it with sand fucked me literally. When i take the rock out all these sand were hooked ON MY ROCK ! how can i take all these sand from my rock ?!?!?!? it's hooked with the cement.... HELP PLEASE !

[@eddiekern]

To keep the cement moist while it sets up. Cement requires moisture to set up properly.