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FAQs about Faux Rock

Related Articles: Marine Landscaping, Marine BiotopeLive RockReef Systems, Refugiums

Related FAQs: Faux Corals, Live Rock 1, LR 2Curing Live Rock, Live Rock Selection, Shipping/Moving, Placement, Lighting, Water Quality, Live Rock Studies in Fiji Collaboration & ChartsCopper UseMarine Landscaping, Marine BiotopeSumps, Refugiums

A "work in progress" of built in artificial rockwork by Rolf Bandsma. Photo by him. 

Man made LR in reef tank  2/24/10
Hey guys, just a quick question. I have done a ton of research on man made liverock, and would have no reservations about using it in a sps dominated tank except that I am setting up a system, and rather than buying new rock, I bought old off of others. Some of the rock appears to be man made on close inspection (looks like Walt smith stuff), but I have no clue what the source really is,
<By colour, texture, Walt's stuff is pretty distinct. No one else makes such in any equivalent volume>
it came out of a tank that had highly successful coralline growth, is there any reason that I should not use it in a 300 gal system? Its about 35 lbs of rock in question
<Likely is fine>
<A good idea to add some new to this... for reasons stated on WWM (biodiversity/abundance, solubility...). Bob Fenner>

Fake "Texas Holey Rock" A link to the product would have been helpful. 10/1/2009
<Hi Becky>
I'm wondering if you would give your opinion on this type of rock. An etailer is selling man made Texas holey rock as safe for a reef tank.
I emailed them as to what the rock is made of, and they replied with "sand and vinyl."
<Sand and some type of polymer binder perhaps?>
The pieces they sell are large. 31" x 16". I am tempted to use a piece in my tank. I am not trying to save on cost here. I like the idea of the stability of the structure.
<Are they selling this for aquarium purposes? Can you send a link to the product?>

Re: Fake Texas Holey Rock 10/1/2009
<Hi Becky>
Here's the link. http://www.glasscages.com/?sAction=ViewCat&lCatID=71
<Ahh, thank you.>
I did not include it earlier because I didn't want to "advertise" for the company if the product isn't what it says it is.
<You should be good to go with them. They have a mixed reputation as far as their tanks are concerned, but the rock should be fine.>

Using DIY Rocks  10/6/08 Hello Crew, <Hello there!> I read through the exhaustive articles on bioballs and believe I actually have a unique question on them. I am starting a 55 gallon FO with 50lbs of DIY live rock (dead rock made from oyster shells and Portland cement cured 3 months to prevent chemical leaching) and 50 lbs dried out live sand. I plan on using a wet dry trickle filter with bio-balls (because my DIY rock has unknown filtering ability at this point and its already in my basement collecting dust) and placing live sand in the bottom of the filter with Chaeto. <Depending on the porosity of your rocks, it could be quite a good filter, crushed oyster shell is great for good porosity so you should be fine. Prior to using, put in water, let it sit for a week and see if the pH is below 8 -- to make sure that it's "cured"> I never plan on placing corals in this tank due to the outrageous cost of large PC and MH lights. <If you search this site, you will find that there are a few corals, although very few, that will thrive using NO or VHO fluorescents>  As a FOWLR tank I know that nitrates are of lesser concern but I want my DIY rock to grow some coralline. <Nitrates are always a concern, regardless whether it's FO, FOWLR, or REEF. You should always strive to keep your nitrates as low as possible. High nitrates promote algae growth, which inhibits coralline algae growth, one of your main reasons for writing us.> So now to the questions: 1. How high can the nitrates get and still grow coralline algae on my DIY rocks? <Coralline algae will grow providing there are spores floating in the water. You can "seed" your tank my using a real piece of live rock with good coralline algae growth, or....getting someone you know to scrape the coralline algae off their glass and giving you the flakes.> 2. Do you think I should just dump the balls and hope that the DIY rock can keep up? < I wouldn't use the bio-balls. Let the tank cycle naturally..if it goes through the cycle, your DIY live rock is doing what it needs to. I have to add that you will need good circulation around your live rock so that it can do it's job as a filter. Having said that, determining the bioload for your live rock is another story, however, as already said, if your DIY rock is porous, you should be fine. If you find that your nitrate level is climbing as you add fish, then you may consider adding the bioballs as added bio-filtration.> 3. With the balls dripping the nitrate rich water onto 2 sources of nitrate conversion, (DSB and Chaeto) could I keep the bio-balls and get the benefits of the added oxygen? 4. How high can I let the nitrates get and keep the fish comfortable? <Please don't think in terms of "how high can my nitrates go?", but rather, "how can i keep my nitrates as low as possible?" Doing a search for 'nitrates' on this website will get you a ton of information on this subject. You can start with this article: http://www.wetwebmedia.com/nitratesmar.htm> Thanks <Best of luck with your new system...BrianG>

Aragocrete vs. Epoxy Resin - 04/06/08 In the last post someone asked about the merits of Aragrocrete as a substitute for live rock. <<I recall seeing this…>> Robert Fenner was against this as this is biologically inert, heavy and not porous. <<Mmm, can be "porous"…but as one who has made and used a like material I must agree with Bob…is a "very" poor substitute for even dead/dry "live" rock>> As I live in New Zealand, live rock is not available so I did make some concrete sculptures to have something in the tank. Dead base rock is available and the porous nature of this may have some more merit. <<Among others…>> My experience with concrete is that it is an absolute pain and would never use it again, <<We are in agreement here>> and in the end I removed it, smashed this up and it went to the dump. It is very heavy, and eventually almost impossible to clean. <<I also believe it to promote nuisance alga…other issues/problems>> I have a high tech system relying on sulfur reactors, deep sand beds, large sump, sintered glass beads and fluidized bed filter and two protein skimmers and ozone to support my lightly stocked 300 litre tank. (a highly redundant system) <<Neat>> My nitrate and phosphate levels are zero, and I have no major rubbish algae problems. What I did to replace the concrete is to use epoxy resin plus crushed marble to create open hole shelving for my LPS corals in a low weight modified floating reef system. The corals just drop in the holes. <<A better solution than the concrete…but still, offers little if any buffering capacity and is of no benefit re soluble bio-minerals. But to be fair…these can be easily supplemented>> Mine dismantles into three layers, and assembles securely in one minute. <<Handy>> You can even color the rock with artificial coralline algae with colored epoxy resin paste. There is still some need to scrub the rocks for some golden brown algae a few times a month, but the shelving can be removed, scrubbed and corals placed back in their split level locations in holes, sand bed vacuumed, stirred, glass cleaned in 20 minutes. <<Hmm…I doubt that "scrubbing" the rock is necessary, or even desirable>> There is no need cure the lime out of the epoxy construction, and it is very strong allowing more creative and thinner and structures that are a fraction of the weight. <<Very nice>> While not natural or biologically active, it is pragmatic and functional. <<I guess that would depend on one's sense of aesthetics [grin]…but it is certainly different/interesting>> Note how the corals can be safely kept apart and the deep sand bed remains almost totally uncovered with no dead spaces in the circulation (currently 10,000 litres per hour) There will be other more creative people that can come up with an even better more natural design than mine. I have enclosed a picture of my tank. Mike Lomb <<Thank you for your contribution, Mike. It will be posted for other's perusal. Regards, EricR>>

Aragocrete  4/5/08 Hi there, <Richard> I know there are several of you guys who answer these e-mails and that you all have your own opinions. <Ah yes. Thank goodness... with rationales> I am stuck on a small island (it's OK, I don't need help with that!) <Oh! I've been on one the last couple weeks... Mabul, Sabah, Borneo, Malaysia...> and as a consequence getting hold of live rock is a logistical and financial nightmare (yeah it's porous but it's still pretty big and heavy). <Perhaps just a short dive...> I was wondering what your opinion is on aragocrete? <Am decidedly NOT a fan myself... too much work, too caustic, ugly... no real surface area...> I have seen some of GARF's promotional material on this saying it's as good as live rock, <... no> if it's given long enough. Is it as porous as good live rock? <No> I understand it will need quite a while to leach out the ph and also to introduce life, bacteria etc. <Mmm, yes... a friend, Walt Smith, started making such "faux rock" in Fiji some years back... placing it in the sea for months for culturing... is more harmful, trouble than just collecting the real thing... really... The cement to make the phony rock... is made from coral...> But essentially I want to know if, even given an ideal scenario i.e. well made, well cured, seeded with live rock/rubble, is it a close or very distant second to live rock? Richard <IMO this is an extremely poor substitute; the only function/place of which I'd employ it is in VERY large (thousands of gallons) systems as a base... even then cinder blocks would be preferable IMO. Bob Fenner>

Marine Aquascaping…Building Large Rock Structures - 03/01/08 Are there any products or substances such as mortars, plasters, or plastics that can be used in marine aquariums to fuse together pieces of dead or live rock and build large rock structures? <<There are…though for building a structure from "live" rock you will be pretty much limited to "mechanical" fasteners of some type (e.g. - Acrylic rods inserted through holes drilled in the rock) as using something like a hydraulic cement; though it could be applied "submerged", will raise the pH of the water too high (about 12.0) and destroy the life in/on the rock>> I am looking to build a rock structure to hide a series of standpipes and returns in the center of a tank that will be 48" tall. <<Will require some thought/planning…but can be done>> I am worried that just gluing together the pieces will not be stable enough at this height. <<Indeed… Best to use some type of "skeleton" or frame upon which to attach the rock…and easily crafted from PVC pipe and fittings>> I have heard that products like Thorite are better than "standard" cement for this type of application. <<About any good "concrete" mix used with a plasticizer admix should work, I would think. But going this route, the end product is going to be VERY heavy>> I have also heard that there are water-proof plaster products that can be used however my goal is to use products that do not require long term curing due to leaching. <<I don't know that a "plaster" would have the "strength" needed…as that provided by a concrete (aggregate) product>> Any suggestions are appreciated. -Adam <<I think for both performance and to lessen weight, a foaming Polyurethane adhesive may work best for you. The Polyurethane foam will not only form a chemical (glue) bond, but will "expand" in to the irregularities of the rock creating a mechanical bond as well. The Polyurethane is amazingly "sticky," and is inert, as well as surprisingly strong, once cured (about 24hrs). You can get it in "black" from aquatic (pond) sources, or use the slightly less expensive GREAT STUFF insulating foam found at most any home center/hardware store. I suggest you build the structure in segments outside the tank and then assemble/glue the structures together with more foam in the display. Don't forget to use a PVC framework to support the rock and foam…and do be especially cautious if using the foam in/around an acrylic tank as it may disfigure/etch the acrylic on contact. I used this material to build some large rock structures on PVC frames for my 375g reef some four years ago, and the foam/structures have held up very well. Regards, EricR>>

Riffkeramik  10/25/07 Hello. <Howdy> Do you know where I can purchase Riffkeramik in the U.S.? <Did see a demo set of pieces of this decor this year... Don't recall what part of the west I was in at the time... nice, stackable pieces of size... but a bit pricey in much-diminished (thanks Geo. and other idiots) dollars> I'm trying to find a dealer or supply store that carries it, but it seems like it is mostly available in Germany. <Yes... and elsewhere in W. Europe> Thanks for your time, a. Kim <Do keep looking... Am pretty sure the fellow I saw/met was importing it... Will be advertising somehow. Bob Fenner>

Tremors! Rock placement  - 5/1/07 OK, this is a weird one. I've had this tank set-up for years, without anything like this ever happening, so it's really throwing me. (Tank is 150g, 2.5" live sand, 200+lbs live rock, assortment of fish, shrimp & purple lobsters, serpent stars, hermit crabs, mostly reef-safe stuff but haven't made the jump to corals.)  Anyway, it started a few weeks back, where I wound wake up and find that the fish (perhaps the gobies) would have made a tunnel under some rock, and piled some sand against the front glass. I would level the sand out across the front and move on. Then, the tunneling/piling started getting more extreme. (level out and move on) After a couple weeks of fighting this, this morning I wake up, and there are 3 enormous piles of sand (8"-10" deep at the peaks) across the front of my tank. <Wow!> The rock pile has clearly settled a bit with the undermining, and there is visibly very little sand left under the rock. (Kevin Bacon would know what to do!)  Weird, yes, but my concern is with a rock pile that heavy, that the sand was acting as a cushion between the jagged, heavy rocks, and the possibly breakable glass bottom of the tank. Should I be concerned? <Yes.  This is actually a reason to be concerned.  The rocks need to be sitting on the bottom, with the sand around them, to avoid this very situation.  If they are on a cushion of sand, this undermining can cause a big crash.> Should I keep fighting them and having them retaliate? <Well, I would let them pile, but the remaining cushion under the rocks needs to come out.> Should I remove the excess sand altogether? <I wouldn't, it seems to be providing lots of entertainment for someone. I would just make sure the rocks are planted firmly enough to avoid a rockslide.> Why now? <Hmm.  Has the water flow pattern changed?  I get some pretty big piles from sagging powerheads sometimes.  Any new fish to stir up territoriality or spawning behavior? > Yes, this is a silly one, comparatively, but I'd hate for the bottom to drop out of this tank because of aquatic interior decorating. Thoughts? <Remove as much as possible from under the rocks and assure they are well settled.  Maybe they already settled all they way?  If you think there is still a cushion under the rocks, then they may have to all come out, remove sand, replace rocks, then replace sand to get it more stable. > Your friend in RI, -Pat <Cheers. Alex>

Water chemistry question... Ca reading, cement rock...   4/21/07 Hello crew, a good day to you!    I have a question about a 55 gal tank that I have recently set up with the end goal of creating a thriving reef tank.  So far I have the 55 gal display, with a 17 gal sump which house the protein skimmer in the first chamber, a refugium in the second, and the third is the return pump and a couple of heaters.  The tank has cycled, I currently have one green chromis damsel, 30 Astrea snail, 10 hermits, 3 mithrax crabs, <Do keep your eyes on these last> and I added 45lb of Fiji live rock this week.    I initially made my own rock (50 lbs) using the crushed oyster shell, Portland cement trick, <Bunk...> but even after curing for 2 mo in fresh water and 2 weeks in salt it was producing very high pH, and high calcium levels, <Yes... typical> so I partially ditched that scheme.  I retained 4 of the pieces (~10lb), couldn't handle tossing them altogether after spending/wasting all that time making the rock.  My problem is that I am still getting calcium readings of 750ppm. <...!>   I read a QA on WetWeb that said that calcium levels cannot get this high as it would precipitate out a lower levels, <Mmm, can be this high... but at the "expense" of other chemical species... e.g. alkalinity (carbonates, bicarbonates esp.)> but I have gotten this reading on two test kits.    I am waiting for the water chemistry to level prior to stocking fish and inverts.  I was wondering if there is any way to reduce the calcium levels other than just by doing water changes? <... let's see if I can make this bit of reaction theory clear to you... By supplying the high degree/source of readily soluble calcium (the cement)... you are and will continue (for some time...) to drive the concentration high... You could "waste your time" and money dropping in chemicals to counteract the high alkaline earth element situation... but I'd just remove this "rock", maybe try either just letting it soak in a barrel of water for months... or pour in some inorganic acid source (outside)... like Muriatic (3M HCl...) to neutralize... this will dissolve the outside bits of this faux material... exposing new... till all the cement is gone really...>   Would lighting intensity have any effect? <? On calcium concentration? No> I have two 96 W pc bulbs but am only running one bulb for about 7 hr/day as I do not currently have that high a lighting need with the current inhabitants. Also, are there any other consequences of having high calcium levels besides hindering the buffering capacity/unsteady pH levels?   Thanks Ben   Madras, Or <Oh yes... You should have read: http://wetwebmedia.com/marine/maintenance/index.htm Scroll down... Bob Fenner>

Calcium Levels...Is It From GARF/DIY Rock 4/17/07 Hello, <Hello Graham> A little over two months ago I transferred the livestock inhabiting my existing 55 gallon reef over to my new 90 gallon setup. At that time I decided to add a 15 gallon Caulerpa refugium with a 4" DSB. I also added two large rocks I had made using the GARF Aragonite/Portland Cement formula. <I'm not really fond about some of their ideas.> About three weeks after the transfer and the addition of the refugium I began testing calcium levels with a Salifert Test Kit I had just purchased. Over the last two months I have got the following results, in order from oldest to most recent: 540, 530, 590, 650 ppm. Based on the postings in your forums the latter is not possible. However, I recently tested saltwater made with fresh water from the RO/DI and Instant Ocean Reef Crystals to SG 1.024 and it tested at 330 ppm with the same test kit. This would indicate that the test is working properly. Also, since the beginning of this testing I have been tracking the Alkalinity with a Salifert KH Test Kit. I have tested it over this two month period and got the following results in order from oldest to most recent: 5.8, 6.4, 8, 7.5, 7.7, 6.4, 6.4, 5.8 ppm. During the time between the 5.8 and 7.7 readings I had been supplementing the tank with Kent Pro-Buffer dKH. When I stopped supplementing it fell back down as expected. I have done several small water changes (~10-15 gallons at a time) with no real effect on the calcium level. I can only assume that these calcium levels are a result of adding a large volume of fresh aragonite to the system. Is this a correct assumption? <Yes and No.  Depending on the type of Portland Cement you used, and I'm assuming you used a ASTM type, the calcium levels you are reading are quite justified.  A major component of this type of cement are hydraulic calcium silicates along with calcium sulfate as an inter ground addition. Now, in addition to the aragonite, zowie!> Also, what is the best course of action? <Too late now, but if I were to make rockwork with this method (and I wouldn't for the obvious reasons you mention), I would have let it cure for at least two weeks, and then, soak it in freshwater for another two weeks doing daily flushings with a garden hose.>   Should I perform several large water changes over the next few weeks to get the excess calcium out of the water? <At this stage, I would remove the DIY rock and do let it soak in freshwater and completely change the water every couple of days until a two week period is completed. Yikes, what am I saying, just throw the damn stuff out and get some real live rock, is not worth the bother.> All my corals have been suffering since the change (various LPS, mushrooms, zoos). They are somewhat bleached and never fully extend anymore. <Could be from another additive found in some types of Portland Cement...tricalcium aluminate.> Is a very high calcium level detrimental to their health? <Cannot answer that, Bob?> <<Oh yes... trouble in several regards... See the related and influenced factors of pH, alkalinity... RMF>> I am not sure if this is due to the excessive calcium levels or the fact that my MH?s are well overdue for a change (new ones are on their way as we speak). <I'd bet from the mess you created.> All other tank parameters that I monitor (Nitrites, Nitrates, Phosphates, Ammonia) are in check. Your advice is much appreciated. Thanks, <You're welcome.  James (Salty Dog)> Graham

Refugiums, Lighting, & Frags, Oh My! - 03/06/07 I have read many pages on WWM and have found a great deal of info. <<Excellent to know>> Thank you. <<And thanks to you for "using" the site>> The information shared has enabled me to have propagated my first mushrooms and xenia in a ten-gallon tank for trading with the LFS. <<Cool>> I am also starting propagating to place specimens into our larger tank coming soon- a 40-gallon with a 30-gallon refugium, 7-gallon sump. <<Neat...and interesting you have opted for a larger refugium versus the sump.  Most hobbyists go the other (and maybe misguided?) route>> I plan on using all man-made live rock, and have some pieces curing. <<Mmm, speaking from experience here...I recommend you "don't" do this.  Use a couple "specialty" pieces for caves/ledges if you wish, but do keep the bulk of the rock as "natural" live rock.  Regardless how "real" the man-made rock appears, it falls well short of the real thing in all other aspects.  Even when composed of some aragonite material, the man-made rock will not have the buffering capacity nor contribute bio-mineral/earth elements to the tank like natural live rock.  Obviously the man-made rock will contribute NO BIOTA at all to the system...yes; it will populate to some extent...but will never come close to the real thing.  And maybe the biggest consideration here for me...it has been my experience that the first thing to colonize the man-made rock are species of nuisance alga.  It is anecdotal proof for sure, but it seems to me the cementous surface is prime habitat for nuisance alga.  Sooo, don't be swayed by the seeming value in man-made rock...tis false economy in my opinion>> The 40 is in-wall, and the 30 will be less noticeable for frags/refugium in another room. <<Ah, I see>> I have a couple questions if you can respond or direct me to the answers I would be much obliged. <<Fire away>> I have read about refugiums with 24-hour lighting housing Caulerpa utilizing lighting reverse to the show tank (on when the main tank is off). <<Mmm, a contradiction here.  24-hour refugium lighting would indicate the lighting is on all the time...regardless of when the tank lighting is on (and is best when housing Caulerpa species of macro-algae to preclude a sexual event...in my opinion).  I think what you mean is "RDP" or "Reverse Daylight Photoperiod">> The intent of reverse lighting is to eliminate ups and downs in oxygen, thus causing other water quality issues that I don't claim to be able to explain, but seem to understand with fair accuracy. <<Several things going on actually as a result of the photosynthesis...with the primary benefit being pH support/stabilization>> My wife is into the idea of a reef tank, fascinated by the little creatures in our 10-gallon, but doesn't support the 'glowing closet' of reverse lighting or 24hr lighting.   <<Mmm...a dilemma then...>> So... Q: If oxygen is the main issue, can we as aquarists violate the "keep it simple" rule and simply put an air pump on a timer in the refugium when lights are off to maintain stable water conditions? <<Oxygen is not the "main" issue re a refugium.  Use of a protein skimmer will keep the water saturated with oxygen...and even vigorous water movement at the surface of the tank greatly facilitates gas exchange.  Though not the "best" method maybe...but if the lighting at night is an issue, simply run the refugium lighting in synch with the display tank lighting>> Q: If I fill the 40g and 30g with salt water, placing all the goodies <<...?>> from the 10g into the system, can I place my soft corals into the tank once the water clarity is fair? <<Though moving some rock/water from the old system to the new will likely speed cycling, I would still wait a few days and move your livestock once the water tests show it is safe to do so>> The 10g has some coralline growth, bunches of copepods dancing/sticking around, some Caulerpa and the sand is crawling with critters.  How long should I wait to place cuttings/frags into the show tank? <<Ideally?  If you have the capacity to run both systems I would let the new system sit empty/run for a month at least (the more time the better in the long run) if only to "mature" the system a bit before moving in the livestock>> The 40g will have much more appropriate lighting and I can't wait the get the extra space to frag/propagate. <<I understand your excitement...but try to not let it overshadow your reasoning>> Q:  I don't see any reason I shouldn't divide the refugium into two parts, one for a deep sand bed, the other for frags/propagation? <<Is up to you...>> Any suggestions on proportions? <<Always difficult to mix usage in a small tank...but the bigger the better for the DSB.  Perhaps adding a separate inline frag tank is in your future>> Q: Can one safely use latex paints in the same room as a running reef system? <<Has been fine in my experience, yes>> Thanks for fielding these questions if you are able. <<Quite welcome>> Coach Tom Stephan <<Regards, Eric Russell>>

Artificial "Live" Rock - 11/15/06 I am currently setting up a 300 gal. <<Neat!>> I have a 30-gal sump, separate 50-gal refugium. <<Cool...and interesting that you opted to use the larger vessel for the 'fuge...goodonya>> It will have 400 lbs sand.  My question, I have ordered man-made rock (aragocrete) from a guy in Gauthier Mississippi, he has them made, and now resting in the ocean for me curing, etc. <<You do realize this rock will have no buffering capacity/benefit the system with dissolution of earth elements...>> They now contain various live critters, shrimp, crab, tubeworms etc. <<Yet unfortunately, will never have the bio-diversity/bio-density of natural live rock>> Should I have him pull the rocks up and keep wet and hope some of the critters will survive, don't want to import a lot of pests or let them dry.  I will be picking up rock and sand and transporting home in large 55 gal covered Rubbermaid containers, then introducing to the knew set up. <<I would have the rock left in the ocean as long as possible.  Once you get it home I suggest "curing" the rock outside the display while keeping an eye out/removing any "pest" organisms found (likely Aiptasia and mantis shrimp).  Regards, EricR>> Re: Artificial "Live" Rock - 11/16/06 Thanks, <<Welcome>> I am also going to add about 120 lbs of live rock from my current 90-gallon setup; I'll keep a close eye on pH. <<Ah, good...but pH spikes from the aragocrete should not be a problem if the rock has been cured/been curing for a couple months>> I figured I'd try the man-made, aquarium is big enough to handle fluctuations, and I won't overload it. <<Excellent>> I'll handle the rock as you suggested. <<You will be glad you did.  Regards, EricR>>

DIY "Live" Rock  8/2/06 Hi, <<Hello>> Have you heard about this DIY live rock made from cement? <<Indeed I have...have "made" several hundred pounds of it myself...though it is anything but "LIVE">> Do you know if it actually works? <<Depends on your definition of "works".  Is it a replacement for live rock?...Not even close...  Do I think it has a place/purpose?...Yes, when used sparingly to create "special" features (e.g.- adhered to PVC frames with polyurethane foam to create caves/ledges)...>> Can you recommend a good process for creating LR?  Or is this all just a internet hoax? <<Not a hoax...a simple Google keyword search (DIY live rock) will yield several methods/recipes for making the rock>> Also is there any other types of rock I can use in my reef tank to just build up some height and depth that is cheaper than the $9.00kg I buy? <<Mmm, perhaps use "dry" reef rock if you can get it...better than the DIY rock which contributes little if any earth elements/real buffer capacity>> Thanks Adam, <<Regards, EricR>>

Limestone For Live Rock - 01/06/06 I read an article that they had used Quarried raw limestone for a platform to seed with a live rock.  They said it was easy to form with a chisel and drill and made a good platform for many invertebrates.  Given enough time it would become like live rock.  What do you think? <<It will become "live", yes...but will never have in my estimation the biodiversity/population density of naturally occurring rock that has been formed and residing in the sea for decades.>> Problems? <<Very heavy...>> Thanks for your time, Tom <<Welcome...EricR>> - DIY Live Rock - Dear Crew, A recent poster asked some questions about GARF style Aragocrete. I've been reading about this, and while back bumped into a forum where there were a whole bunch of users who tried it and shared their experiences in detail. While I cannot remember the site, I do remember the take home points. 1. Effort should be taken to make certain that the finished product is quite porous. This is important to the later function of the live rock. 2. If you use the very best low ph cement, you'll thank yourself later. 3. You must indeed cure for a great deal of time. 4. Circulating the curing water makes a great deal of a difference, particularly in helping mediate the problem described below in #5. 5. If Muriatic acid or other fast curing techniques are used, one should be aware that the outside might be better cured than the inside. This may result in a period where curing appears finished but is not. pH may even out, but spike later as the material leaches. In other words, take care and don't rush. #5 was taken directly from some folks who got their PH to an acceptable level in curing, but had spikes alter, presumably from the cement in the rock. Joe San Diego CA USA <Thanks for sharing. Cheers, J -- >

- DSB, Sand Selection, and DIY LR Questions - Hello, WWM Member! It's so nice to have such a great resource to help those of us without a lot of hobby experience.  I'm still in the planning stages for a 70-90g peaceful reef tank, and I'm confused on certain points.  I have done TONS of reading on WWM regarding these questions, and I haven't found consistent answers... perhaps some of my questions have no conclusive answers! First, regarding DSBs.  I know that optimally, 6"+ is best.  Is 6" optimal? <Six inches is the minimum, not optimal. Eight to ten inches would probably be optimal, if not always practical.> If not, what's the optimal depth?  (I know that making it too deep can cause hydrogen sulfide problems; at what depth do problems develop?) <Not sure this is empirical. I have a 12" DSB sump that's been running for a year and have had no problems with hydrogen sulphide. Think sulphide problem may result from sub-optimal depths, where the proper bacteria that would make use of this stuff do not exist.> I've done a lot of reading regarding substrates, and I'm confused.  I've read that Jawfish and other burrowers are best kept in fine sand with some coarse material to aid their burrowing, and that these fish move around the bigger pieces to their liking; I've also read that coarser material mixed in won't harm anyone.  However, I've also frequently read that you shouldn't mix substrate sizes so channeling/packing is minimized. <I mix substrate sizes all the time - especially in the fish tank - seems to allow for better fauna development in the substrate.> So, the question: if I'm keeping Jawfishes, gobies, and the like, what should I do?  Should I stick with pure sugar-fine aragonite sand, or add some crushed coral, or add even coarser material like crushed shell? <I'd do all three.> If I should have coarse material, what ratio is best? <Perhaps 1/3 of each.> I just want to make sure they have the best substrate possible. Also, I'd like to make some GARF Aragocrete "Reef Tables" and a couple caves for my tank (I'll have plenty of "real" live rock, of course).  I've heard some people have no problems, and others make claims that the cement adversely affects tank chemistry.  What's the truth? <The truth is that anything cementatious would need to be cured for a while - months - in a weak acid solution (vinegar would do) to help bring down the highly alkaline nature of cement products.> Would I be foolish to use Aragocrete, or will I be fine? <No... this has been done for decades in public aquariums and the like - is perfectly viable as long as you take the appropriate precautions.> Oh, one last thing, if I may.  I plan on principally keeping quiet fishes, like gobies, Banggai Cardinals, blennies, and perhaps a Jawfish or eventually a mandarin (with a refugium, of course).  But... I (and my wife) would love to have a yellow tang (Zebrasoma flavescens).  Would it be too boisterous or aggressive a feeder to mix in this type of tank? <Would be fine.> I'm worried that the other fish wouldn't get enough food... Also, is there any species of clownfish that could coexist peacefully, as well, or are they too aggressive? <My favorite are the true and false percula clowns - they seems to be the most docile of all the clowns and seem to get along with just about anyone that won't eat them.> Thanks so much for your time and help; I truly appreciate your advice. Scott <Cheers, J -- >

LR, Filter Media and Dottyback part 2 2/22/05 Thanks a lot for all the information. <Glad To!> Is it better to have LR submerged in water or have water flow over the LR? <Submerged. It is decorative as well as functional.> Where can I get information on making rock? <www.garf.org or Google search for DIY live rock.> Thanks a million, Mohamed. <Always a pleasure! AdamC.>

Live Rock Recipe Date: Thu, 3 Feb 2005 Thank you for the amazing website!  <You're welcome> I was wondering if any of you had a recipe for making synthetic live rock? Aragonite mixed with Concrete? Crushed Coral? Soaking Time? Bleach Rinses and Dechlorinators?  <Jason, go to the GARF link posted here. They have a recipe for "Aragocrete". http://www.garf.org/ > Is this a good way to go or should I just suck it up and buy more live rock? <Many people have done this. As long as you have live rock, the artificial rock will eventually be seeded by it.>  I have an established 125g Reef with softies and 90lbs of live rock (not enough for aquascaping purposes). I am worried about adding more live rock to the tank (even if it is cured by my LFS).   It would also be nice to save for some other toys. Thanks! Jason  <As long as it's guaranteed cured, no need to worry. But a 150 lbs of rock is more the norm for your tank, so if money is the issue, give the Aragocrete a go at it. James (Salty Dog)>  Synthetic Rock Hello, <Hi! Ryan with you today.> I am starting up a 110 gallon reef ready tank.  its predominately going to have fish, with some inverts such as crabs, shrimp, an anemone, etc.  I bought this product from Corallife called a Reef Rock replica.  it looks amazingly like live rock!!  and they are hollow with various holes in them for hiding places.  my question is. instead of using live rock, could I get the same biological benefits of live rock if I filled these hollow fake rocks with some sort of biological material, such as the macaroni type stuff you put in canister filters?? <No, not at all.  The filtration process of the water slowly passing through the rock cannot be duplicated.  You can, however, use alternative methods of filtration, such as a deep sand bed or skimming.> if not this stuff, what would be best to put inside these rocks???? <I don't use filter media in my aquarium setups, but here is a wealth of info about the stuff: http://www.wetwebmedia.com/marmechf.htm.  I'd also try the wetwebfotos.com message board to see if anyone has a history with this type of synthetic rock.  Good luck! Ryan>  thanks.  Jeff

Hard aquarium questions Dear Mr. Fenner, <Lisa> I was wondering if you could answer some of my questions about the way aquariums tanks are currently made. I have seen the debate between using glass or using acrylic for the tank but I rarely see any mention of polycarbonite which has been used at Walt Disney World in the living seas. <Mmm, me neither. I know of the use of this impact resistant material in greenhouses... its order of magnitude strength greater than acrylic...> I rarely see it mentioned at any of the website businesses making aquariums. It's much stronger than acrylic and so it doesn't scratch. Why don't they use it more often? <Don't know... have you investigated internet sources of information re this materials properties? Perhaps it bows badly in small thicknesses...> Also why are the stands often made out of wood when they could be subject to water damage? Why don't they use a design more waterproof? <Mmm, cost of production, materials... legacy of using wood> I also have a question about how breeders advertise mailing people certain fish and corals. I wonder if that is safe, or will the sea creature be killed in the process? <Sometimes> Also is it truly possible to help the environment through the captive bred programs? <Not necessarily... I have asked friends/associates in the trade similar questions. What sense does it make to construct artificial "live rock" that utilizes cement made from... corals and their reefs?> Thank you for taking the time to read my e-mail. Lisa <Thank you for writing> Prefab Rockwork For A Reef Tank I want to try the foam insulation and Live Rock combo on the back of my aquarium. Instead of putting it directly on the back of my aquarium, I am going to buy some acrylic sheets and add the foam/rock to those. I plan on using glue to attach to the back of the tank. I am not going to empty the tank. <I have seen this done on several tanks, and the effect can be stunning if done right!> 1) What Glue would you use for this? Has to be waterproof and reef-safe. <I believe the product that would work is a thickened acrylic glue called Weld On #16. You may want to do an internet search on this product, and consult the manufacturer about its suitability for this use> 2) Do you have any articles which reference this technique? <I believe that there was a piece on this in an older issue of "Reefkeeping Magazine" on the Reef Central site. Do search there.> Thanks for your wonderful Free Knowledge Base for use reefer addicts!!!! Adam Kooperman <Glad to be of service, Adam. I hope that I am leading you in the right direction! Best of luck with this project! Regards, Scott F> JamesF, NMA, Carbonate use... Yo Bob, I was reading your invert book this morning and came across something that caught my attention.  Under the section on live rock it says aquacultured rock is quarried limestone that is a "non-renewable source of a very finite quantity that dwindles every time it is mined..."  If you think that's bad, you're gonna hate these numbers - from an article about the huge Everglades restoration project. <Well... don't exactly agree with the extreme tenor of the statement... as the carbonate used as such is a very non-limited resource as you know> "They say the plan will respect the property rights of miners who already own land in the area, while steering their quarries as far from the park and the county's well fields as possible. It will harvest 1.7 billion tons of lime rock that will promote economic growth. It will create rectangular water bodies that won't be true biological "lakes" but will block Miami-Dade's seemingly unblock able westward sprawl. If the new technology works, the Lake Belt will eventually boost local water supplies and help rehydrate the Everglades." "Every day, 3,200 trucks and 400 rail cars full of crushed rock leave the Lake Belt, carrying 40 percent of the aggregate used in Florida's concrete." from THE SWAMP: Mining the Everglades in Order to Save It By Michael Grunwald Washington Post Staff Writer Monday, June 24, 2002 http://www.ussugar.com/sugarnews/everglades/swamp_series/swamp_part2.html <Uhh, that's some volume, mass of material!> If you have the time you should read this series of articles on the project.   It'll piss you off real good.  Apparently the whole thing is just short of a hoax to let mining companies make a fortune ("...an internal Corps e-mail called it "a steal" for the miners, noting that "political entities play an enormous role in this particular beast.") - and will cost 8 billion in tax dollars - but that's a different story.  Anyway, I get the impression that the few barge loads of rock collected for aquaculture aren't going to add up to much compared to this. <Hee hee, to put it mildly... a point I frequently make about the hobby, trade impact scale overall> Other than that, not too much going on around here.  I don't have any classes this month, but I still have to go to the office 9-5 and just hang out.  Been catching up on reading (obviously), doing more writing, etc.  I bought a Canon 10D a couple of weeks ago, so I've been playing around with it, too - trying to figure out all the bells and whistles and the software.   I'd buy a housing for it - but damn things are another $1000.  Won't be happening any time soon. <Rats. Perhaps more pet-fish article writing...> Other than that big purchase I've been trying to save everything I can.  I'm anxious to see what happens with interest rates and Florida's real estate market between now and the time I return. Any chance that you'll be going back to the island this fall?  I know two Japanese girls that want to visit... <Yes, am there now and will be returning for most of October... and... don't have a day job and no commitments that I can think of... so let's chat and I'll haul over to meet you. Bob F> Take it easy, jf

Home made base rock, Quikrete color Hi, MikeD here> Have a question about base rock.  There are many different types of base rocks out there from fossilized coral, stones, and lava that I have seen.  I have even seen some that look like some sort of concrete.  Do some people  make their own rocks?<They sure do, some whole companies, in fact>  I was playing around in the garage the other day and had some fence post concrete that I mixed up and added some red color to.  It looks really cool.  I was thinking of sticking it in a bucket of saltwater for a few days to see how it reacts.  What do you think??<My only concern here is what did you add to color it red? As long as it's inert is should be fine, but many things  we might not expect can react with sea water>  Obviously doesn't look like live rock but if situated right I think I can make it look cool.<That would depend on your "designer arranging, but probably could look beautiful>  I have a 150gal tank that has some live rock now but needs a lot more!!  I don't want to hurt my fish though.<Do a search on curing home made concrete decor for all the details, but if the dye is inert, it should work>  I have 3 damsels, 1 yellow tang, 1 snail, 1 anemone, and one clown fish.  Let me know what you think.<It sounds very possible. My own tanks have red volcanic lava stone as base rock and have worked well for years. Good luck to you!> Thanks in advance <You're very welcome> Bob

Quikrete coloration, fast? Mike D,<Hi again, MikeD here> I used the color that is made by Quikrete.  It is used to color the stones and concrete in driveways, walkways, etc....  It is not supposed to fade as it permanently dies the stones.  My only concern is it causing my water to be cloudy.  Do you think I will have a problem? <As long as you allow it to cure fully, you should be fine, and I wouldn't see cloudiness any more likely than with anything else. Don't forget, if you're making your own you can make a sand free form mold and get as creative as you want in shape!> Thanks Bob<You're very welcome>

Making live rock 6/7/04 Hey again, I have a question concerning live rock I have my 30 gallon saltwater tank ,and I have to put like 25 lbs live rock in it right? <depends on how much if any other filtration you have... but yes, 1 to 2 pounds per gallon is the rule> My question is aragonite rock + concrete mix to make LR safe? <can be made to be safe, but is inferior in so many ways . See our archives or "Reef Invertebrates" book for comprehensive details on why> I do not really wanna spend $150.00 for Fiji rock. Thanks for your help, Jeffery <I can empathize with your desire to save... but this is not a cheap hobby. And if it pains you to invest $150 in the foundation of your system's health/filtration... then its really gonna hurt when you buy a good skimmer and quality lights ;) Anthony

- Alkalinity and Concrete Rock - Hi there Crew, Clayton here; <Good morning, Clayton.> Here is a brief rundown of what I am up to, first of all, I had a cloudy water problem that no amount of advice from anyone seemed to be able to cure so I dumped all my water and set it all up new, I used instant ocean salt and RO water for everything, the tank is 240 gallons with a 30 gal sump, with a Berlin xl skimmer, 2 x 400 W MH and 2 X 40 W actinic blue and 2 x 40 W trichromatic, so here is what I did, when I took my tank down I left it down for a month or so because I also changed the front glass, but in the mean time, my crushed coral I had in 5 gallon pails began to rot or something because the pails were still like half full of water,  so to clean it I rinsed all the crushed coral with bleach, and then rinsed the crushed coral excessively, and also added about 100lbs of aragonite sand, under the advice of the Local Pet Store I installed a "plenum" or so he called it, which is basically a undergravel filter that is not hooked up to anything to promote anaerobic bacterial growth to reduce nitrates or something like that anyway, I do not have too much Live Rock, only like 50lbs or so, the rest is some sort of homemade concrete stuff made by a fellow aquarist, but my problem I have with my alkalinity is that I cannot get it up to the normal level and keep it there, in the past month I have added basically a whole container of SeaChem reef builder, (for raising carbonate alkalinity) which is 1 Kg or 2.2 lbs but every time I add this stuff my alk goes up to about where I want it, like 120-130mg/L (or ppm) but within a few days it is back down to 70-80 ppm, it just does not stay up, my calcium is also unusually high it is like 650ppm which I think might have something to do with it, but I have no Idea what or how to fix it, my PH is also low, steady though at 8.0, however the fish are doing great, and the corals I have are spending 90% of their time closed, except the mushrooms however, which seem to be loving it,  and polyps are also doing fine (other corals are soft leathers) however I also tried to introduce my brittle starfish back into my tank and within the 2 days I kept it in my tank, it didn't move around and one of its arms fell off, and I also go a banded shrimp which looked like it was doing fine, it was eating and running around lots, then one day was dead.  Please Help,   Thanks <If I were to pick out one thing, I'd examine that concrete rock. Concrete rock [and even formed blocks] must be soaked in saltwater for months before it can be used in your tank. When it is new, it can do wacky things to your water chemistry so it must be 'cured' [not the same curing as live rock] and rinsed and cured and rinsed before you put it in your display tank. I suspect that this is the root cause of your troubles... I'd be willing to bet that everything else stems from that. Ask that aquarist if he cures the material and for how long - I suspect that if he has cured it, it hasn't been for long enough. A pH of 8.0 is too low and while some animals 'seem' to be doing fine, you can expect them all to have troubles if exposed to this pH for any length of time. Cheers, J -- > Colored concrete To whom it may concern:  I'm inquiring the use of concrete colorants in concrete mix to add color to the rock I make for  fresh/saltwater aquariums or a suggestion that would add color to it instead of the gray dull color it has  thanks  ..great site you folks have.......Jeff   <As far as I know the oxides used for coloring cementatious materials are non-toxic to aquatic life. If in doubt, you might try a bio-assay (keeping some of the colored material in a tank with some "test life" for a few weeks). Bob Fenner>

Moon Rock in a Refugium Greeting, <Hi John, Don today> A question.  <good thing, I am down to one answer!> I have a 35 gallon refugium with a bottom layer of mineral mud and a top layer of aragonite live sand.  I am wanting to have some life rock as base for Caulerpa (maybe some others but mostly Caulerpa for nitrates) and ......well the Caulerpa on top of it.  <You indicate a reef? Might want to reconsider the Caulerpa and use Chaetomorpha (spaghetti algae) as it gives good nutrient export and has fewer negative affects on corals> The prob is that I lack the funds to purchase more live rock directly right now.   I was wanting to know, if I add some "moon rocks" (manufactured by Carib sea, calcium based I am told) how long will it take for this to gain the benefits of the live rock (algae, bacteria, etc.)?  Or will it even?   <Oh, it will become 'live' in a fairly short time (weeks)> The refugium is the sump for a 200gal reef.  It has an additional sump that the refugium drains into that is another 20 gallons, this is where I put heaters, 2 Berlin skimmers, pumps, were I add additives, and do my top-off so as to not disturb life in the tank or the sand bed in the refugium.  Thanks for the help. Feel free to critique my filter setup.  I am up for improvements all the time.  The pumps are turning around 1400 gph and that is all the CPR overflow will allow.  I don't think this is enough.   <Agreed, John, recommendation is 10-20x for you 2500-5000gph depending on inhabitants> I think doubling it would be better.  Thanks. <My pleasure, Don> John

Concrete base rock I am using some concrete aragonite made rock made by GARF in my tank. I have noticed that my calcium levels without dosing since the tanks inception have stayed at a level 600 using Salifert test. Have you heard of this before. <Yes... it's the cement> My corals are doing very well and have an explosion in snail reproduction. I used the concrete rock which is formed into caves as my base rock. Will this have any long-term bad effects? <Only time, experience can/will tell... do get/use a magnesium test kit... and adjust your levels to about three times the calcium... (with Epsom salts is cheapest)... otherwise the high calcium can be "whittled down" with the use of alkaline additives (I'd start with cheapy baking soda, sodium bicarbonate)... slow and steady... Bob Fenner>

Re: Concrete base rock What is the relationship of elevated calcium to magnesium. I have never tested for magnesium, but will start. 3x the calcium level will be magnesium of 1800..is this correct? <Magnesium should be about 3X calcium to maintain balance in the ALK/CA dynamic and support calcification. Best Regards, Gage>

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