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FAQs about Marine Substrates: Southdown, Play Sand Sources

Related Articles: Marine System Substrates (Gravels, Sands) by Bob Fenner, Marine Substrate Options by Sara Mavinkurve, Deep Sand Beds, Live Sand, Biofiltration, Denitrification, Live Sand, Live Rock, Biominerals in Seawater, Understanding Calcium & Alkalinity

Related FAQs: Marine Substrates 1, Marine Substrates 2, Marine Substrates 3, Marine Substrates 4, Marine Substrates 5, Marine Substrates 6, Marine Substrates 7, Marine Substrates 8, Marine Substrates 9, Rationale, Selection, Reef  Substrates, By Type: Aragonite/s, Coral Sands, Silicates, Dolomites/TapAShell, Collecting Your Own, & Physical Make-up, Size/Grade, Location, Depth, Marine Substrate Cleaning 1, Marine Substrate Cleaning 2, Moving/Replacing/Adding To, Marine Substrate Moving/Replacing/Adding To 2, Substrate Anomalies/Trouble-Fixing,

You WANT calcareous material (i.e. sand made mostly of CaCO3). You want to avoid Silicate based materials and Calcites (not soluble... won't supply biominerals or alkalinity)

Pulverized Limestone as Substrate.       5/16/19
I've spent a lot of time reading on different substrate options for reef tanks. One that was mentioned was the South Downplay sand, which is apparently impossible to find now. As I was going through my local Menards, I saw some pulverized limestone and my curiosity got the best of me, so I looked it up. It appears like it could be a good alternative, but I'm not sure. I've attached a photo of the SDS for your review. Anyone have thoughts?
<Looks like a fairly acceptable composition, The problem with sands not conformed by crushed coral is that they do not usually maintain a constant and stable ph, plus the lack of other essential elements found only in coral sands; I personally prefer aragonite, despite the price difference with other alternatives like the one you mentioned. Still I think you can give it a try, do bear in mind that you should pay special attention to any swings or drops on ph as well as abnormal diatom blooms during the cycling period and the following weeks. Hope this helps, regards. Wil.>

Where Would I Get Cheap Bulk Aragonite Sand? 8/31/10
I was told to ask you guys what the best place is to find cheap bulk aragonite sand, so where do you know sells it cheap (including shipping).
<Mmm, we really do not keep tabs on prices of products. Is best to visit various etailers and compare pricing/shipping fees for yourself. After all, you wouldn't want us to price out a new car for you, would you?>
<You're welcome. James (Salty Dog)> 

Reef substrate 8/1/09
Hello Crew
I am designing a new science discovery center at our high school. I have been a fan of yours for several years and I must say you have pulled me through some tight spots.
<We share!>
My concern at the moment is this, I am building a reef again for the first time in five years. I heard lots of bad things about using play sand for substrate. The concern focused mainly on silica as a problem.
<Yes, can be problematical...>
I am building a 200 gal reef system for display and I am on a budget. I read the following.
Actually, if you can, I'd appreciate you telling me if there is a particular brand name
"<no brand recommendation... all aragonite in the country is collected by one company and repackaged. Just buy the cheapest. Fine aragonite sand from Home Depot (South Down brand) is quite popular>"
<Yes, have added quotation marks... This product is scarce as "Hen's teeth" nowadays, but was a very worthwhile source when it was about>
Is it truly possible for me to buy the sand base from Home Depot. I have been building live coral for a month in my own tank but need a sand bed. I plan to have 4" of sand and then a live rock sculpture for the corals.
Can I go with 3" and which sand type from Home Depot would be fine for tropical hard and soft corals. Presently, at home, I have a 3in sand bed with lots and lots of live rock. I use crushed coral for my seahorses but fine sand in my 100 gal reef.
Thanks for any info you can offer. It is worrisome using someone else's money.
<Do peruse the hobby bb's... perhaps Reefs.org, Aquarium Frontiers... and ask hobbyists if there is a supply of such local to you... You want finer "aragonitic" sand if possible... Bob Fenner>

Utah Sand 10/24/08 Hi gang, I've recently written concerning my undulated triggerfish that has been under the weather lately and was informed that supplying a larger system would probably alleviate what ails her. <Often enough does so> Well, I want to do that but money is tight so I'm wondering if it would be alright to use this oolite sand and rock that we have here in Utah from the old lake Bonneville. I've heard from some people that they use it and it looks just as good as the "regular" sand. I'm wondering if it would be as beneficial as using the store bought stuff. My plan would be to have about 100lbs of the Utah sand and what I have in my current tank, about 50 lbs. I'm upgrading from my 30 gallon to either a 90 or 150, depending on how much cost difference there is. Thanks, Chris. <I do think this sand is worth trying... have read re on Wikipedia, elsewhere... is oolitic, mostly calcium carbonate layered... Perhaps not "as soluble" as more recent marine-derived substrate, but... not likely a big deal. Bob Fenner>

Scott F. if possible Getting to the Bottom of Things (Substrate Materials)  9/10/08 Is Southdown even available anywhere? I have looked everywhere and even online with no luck. Do you have some top secret information? The only sand I have found locally is made by Quikrete which I know is not suitable. <Yeah- Quikrete is NOT too good for reefs, huh?> Thanks for your time this site is wonderful! Sandra <Well, Sandra, I think I referred to a product no longer available. The product is now known as "Oldcastle Sand", and can be found at home improvement stores such as Home Depot, etc. Occasionally, there is a product called "Yard Rite" which is also a similar product found at these stores. You really want to rinse this stuff a bit, otherwise the water will be cloudy for a long time! Do the vinegar test" before using this stuff, or other non-aquarium sand products. Take a few drops of vinegar (acetic acid) and dispense into the sand. If it fizzes, it's calcium carbonate (a good thing!), and is acceptable for use in aquaria. Best of luck! Regards, Scott F.>

New Setup, DSB, Kolorscape Play Sand 11/19/07 Hi, <Hello> I am finishing plumbing my new system and I am looking for aragonite sand for my DSB. I have found Kolorscape white play sand in a local HD and am wondering if you know whether it is safe to use and whether it is aragonite? <Have not personally used it or seen it for sale in my area.> I have tested several samples of different sands including some from a fish store and non bubbles in vinegar. Please advise if I can use the Kolorscape sand? Thanks again, John <I would check some of the major aquarium forums and see if you can find people who have direct knowledge of this product, or contact the manufacturer and find out what it is actually made of and what additives have been used on it.> <Chris>

Re: New Setup, DSB, Kolorscape Play Sand 11/19/07 Hi Chris, <Hello> I called OldCastle and they say that it is silica based... I have also called my LFS and they sell aragonite sand for $1 per pound (expensive!). <Yes it is.> I need about 300-400 pounds for each of my two deep sand beds and about 200 pounds for my display. Is it safe to mix the two together? <That is quite a debate you are stepping into, many say that you should only use aragonite sand while others say that silica based sand is fine. In my experience I have only ever used aragonite sand and have been happy with the results, but there is debate even among the crew as to whether it is necessary. Do a search and you can see for yourself the differing opinions.> Or should I use aragonite in display and silica for DSB or vice versa? My plan was to have 2" in the display (150G, 60x24x24), <Too much, looking for less than 1 inch here.> 8" in the lower refugium for nutrient export with macroalgae and small pieces of LR (90G, 48x18x24), and 8" in the upper refugium for food generation with another type of algae (90G, 48x18x24). Can you please advise? Thank you so much for all your help, John <There is much discussion here on these subjects, check out our section on DSBs and related FAQs to get the opinions of several members.> <Chris>

Cheap Aragonite SandWhat Was It Called Again? 06/17/07 Hello again! <<Hiya Rob!>> Thanks for all your helpful advice about my sometimes stupid questions! <<Only stupid when you dont ask>> I have yet another...! <<Shoot>> I have been searching at Home Depot....which bothers me because I work at Lowes..., <<Hee-hee!>> for the sand that is aragonite based. <<Difficult if not impossible to find of latesupposedly the company that used to provide this was bought out>> I've searched three stores, and asked employees. No luck! <<Not surprising, I havent seen it around Columbia for several years>> What is it called? <<OriginallySouthdown Tropical Play Sand From The Caribbean, distributed by Southdown Inc.Later marketed in the same bag but without the Southdown moniker (bought out?) and distributed by Oldcastle Stone ProductsWhich was also supposedly bought out, and the sand soon thereafter disappeared from the stores. But, rumor has it that some K-Mart stores are selling an aragonite based productthough this too I have not found around here>> Is the sand white? <<Not so muchbut is lighter in color than the silica sands. Aragonite sand will also feel soft as compared to sharp Silica sandand of course, the vinegar test can confirm>> I want a DSB in a large tank, and can really save some money here. <<I can relateI have a thousand-pounds of sugar-fine Aragonite sand in my display, and another three-hundred-pounds in my refugium>> (Its a shame what marketing and packaging can do to prices for the same item outside of our hobby! I guess they figure we have the money...). Thanks again for your help! Rob <<Good luck with your search. Eric Russell>>

Home Depot Sand?   7/8/06 Hello! <<Hello!>> I've been through your FAQs on sand and before I pay the $36 for the 40 lbs of sand at my LFS, I just had to check on this sand called Colorscapes at Home Depot. <<Hmm, don't recall hearing this was calcareous...but that doesn't mean you can't use it if it's not, just won't get the benefit of a buffer.  Best I can offer is to test this sand yourself.  Place a pinch in a small container and add some white vinegar...if it bubbles/dissolves the sand then it is calcareous>> I've used Southdown in my prior aquarium and it seemed to work well (after rinsing and a week of nothing but cloudiness)! <<Mmm, yes indeed...and is what I used as well (950lbs of it)>> I need enough sand for a 120 gallon tank, the calculator on another site says 131 pounds should give me 3".  Any advice? <<You say you've read up on sand, but have you read up on DSBs? ( http://www.wetwebmedia.com/deepsandbeds.htm)>> Thanks! Regards, EricR

Home Depot Sand - 11/25/05 The white sand at home depot has changed from "Southdown" to "Gulf Beach" sand distributed out of state of Illinois.  Knowing that some products contain silica does anyone know if this new product is marine reef tank safe? <<Drop a pinch in to some white vinegar...if it bubbles/dissolves you're golden.  EricR>>

Which Sand? - 08/13/05 Hello Again, <<Greetings>> Your site has been the best thing for the hobbies since glass aquariums! <<Thank you>> My question: I will need aprox. 300LBS of sand for a 5" base, I wanted to put down the first few inches with Home Depot sand to save money, and then top off with live sand.  I cant find Sanddown <<Southdown?>> name by me.  But I have found "silica free" sand.  Is this ok? Thank-you in Advance as Always. Dan P <<Should be fine, silica-free or otherwise.  I have done this very thing with the refugium on my frag system.  EricR>>

Southdown Play Sand 10/25/04 I have read several (well until my eyes started to hurt) of your "articles / questions" over the last few days, and so many times you refer to using Southdown Play Sand.  I have effortlessly tried to find this sand in the Hampton Roads area of Virginia and have come up empty - handed.  Many times you have referred to Home Depot being a carrier, and once I saw Ace Hardware. Tried everyone in the area, plus some other "similar" stores such as Lowe's, and nothing.  Where can I find this sand ? Thanks, Kataryna  (NEWBIE) <I live in the Pittsburgh area.  This sand was quite easy to find in the area for quite a while (at Home Depot), but isn't around any more.  My sense is that they switch suppliers on a whim.  This sand is also sold through other outlets as "Yard Right".  If you have a local landscaping company that deals with Yard Right or Cemex as a supplier, they may be able to order you a truckload (be prepared for a couple of tons minimum, but it will be cheap!)  Do avoid silica based sands for many reasons. If you aren't sure, simply put a pinch of sand in some vinegar.  Calcium carbonate sand will fizz and dissolve, silica sand will do nothing.  Best Regards.  Adam.>

Mystery Sand 12/16/03 Hola all.  love the book reef inverts guys.   <thanks kindly> hopefully a quick answered question for you.  did not see the answer to my question in FAQ so here we go. I live in Florida and can't put my hands on Southdown, yard right, or Oldcastle.  Oldcastle (sand operations in Penn, I believe) supposedly only sells their packaged tropical play sand far south as Virginia. <ironic too as it is pulled from the Atlantic and docked in two places in FL as well as Georgia before barging up to New Jersey for PA> found some leveling sand the other day packaged under a different name (but packaged by Oldcastle stone products).  thought maybe I am being blessed by God for being such a good steward, not paying $1.00/lb. for sand. Question: How does one test for sand composition? silica/aragonite. it is difficult to tell whether each particle is more round or more angled as outlined in FAQs.  a similar question was posted but the response left me guessing: > 3. Since aragonite and crushed coral look so much > alike, how can we tell one from the other by their > appearances? Is aragonite crushed SPS coral? <We aquarists cannot tell visually. It is a molecular difference. The notable advantage is that it dissolves easily and at a higher pH. Calcite is tough to dissolve. We must trust the word and reputation of the vendor along with the experience of fellow aquarists. Many of my friends swear by the bulk media at Champion.> > Sorry to bother you. Thank you for your time. <No bother my friend, always a pleasure.> > Sincerely Samuel so can I run a test for dissolution rates? just wanted to start the 6" DSB. thank you <there should be some indication on the package as to its origin my friend (saying "silica" or "Caribbean" indicating calcite or aragonite).. if not, its fairly easy to tell to some extent. At least, you can narrow it to calcareous (Arag/calcite) versus silica. Silica is sharp/irregular in shape and translucent in color (often tan in off color)... aragonite instead is clean white in color and very round in shape (hence the name/definition "oolitic"). Perhaps more simply... how about just track down the seller and e-mail/ask them. Seriously, my friend :) Best regards, Anthony>

Tropical Play Sand - Southdown or Oldcastle - 8/14/03 Hello once again, <cheers> I've been searching for Southdown Tropical Play Sand to no avail.  I've been to HOME DEPOT and they look at me like I'm nuts!  Tried to special order but they can't even find a reference.  However, I did notice they carry a Tropical Play Sand (from the Caribbean) that is distributed by Oldcastle Stone Products in Easton, PA.  Could this be the same product?  Nowhere is the word "Southdown" on the bag.  It comes in a 50lb. plastic bag and is touted as "soft, sterile, and silica free", although the bag states it is "not recommended for traction or aquarium use".  Hope you have an answer. Thanks Much! Eric <they are one in the same. Very few places dredge for aragonite... AES Ocean Key is one of the very few suppliers as I understand it (distributing to DIY store, aquarium, industrial interests, etc). Thus... the 4 cent/lb sand for a sandbox is the same raw material as the processed and marketed aquarium products. Oldcastle will likely be fine for you my friend. Anthony>

Going from Coral to Sand 1/19/03 I recently went to Lowe's and purchased "Kiddy Play Sand".  It had no  warnings on the bag and just says that it has been washed and cleaned.  Is this ok to use as a sand bed for a reef tank?  I have always heard  Southdown sand is ok to use?  Is there any ingredients I should watch  out for? <Southdown is calcium carbonate sand.  The sand you got is likely silica based.  There is a great deal of debate about weather this is a problem or not, but I would not use it.  If you aren't sure if the sand you got is calcium carbonate or silica, you can confirm it by dissolving a pinch in some white vinegar.  Calcium Carbonate sand will dissolve, silica will not.  HTH.  Adam>

Source of Caribbean Play Sand 1/6/03 I've read that Southdown Play Sand is an excellent, cheap source of aragonite sand for my new 180 gallon aquarium and DSB refugium.  I have been unable to locate any at Home Depot and Lowe's, the two large home improvement chains in Colorado. <Some folks have successfully arranged special orders through Home Depot, but since the sand is distributed out of the east coast, shipping out west is prohibitive (but worth paying compared to aquarium brand prices!).  Do also try to find Yardright brand, which is reported to be the same product in different packaging, often distributed through Agway and other farm and feed type stores.> Both have only locally produced granite play sand. <Local being the key word.  It just doesn't make sense to pay $5 to ship a $3 bag of sand across the country (Unless you are an aquarist!)>. The local marine fish stores have aragonite sand, but at $35 a bag.  I would need to spend several hundred dollars to meet my sand needs, vice the $30 for the play sand.  Do you know of any distributors of aragonite sand in Colorado? <None specifically in CO, but do try http://www.purearagonite.com as a last resort.  Also, just as a disclaimer...  I am generally very strongly in favor of supporting you local fish store, but in a case like this I will suggest that you support them in other ways.  Best regards.  Adam>

-Southdown?- I am setting up a 125 saltwater aquarium for the first time and wanted to use Southdown for a substrate.  I went to the local Lowe's and they have Southdown "Pulverized Limestone."  It looked a little gray and had the consistency of Powered Sugar not regular sugar.  Can I use this for substrate or is it to fine????? <I believe that's the stuff. It's calcium based and really fine, I'd go for it. Try a bag (cant be much more than 4 bucks) and toss some in a bucket, you'll be able to tell if it's just dust once it settles down. If it's way too fine it should be more like clumpy mud.> Also, I went to Home Depot and they didn't have and Southdown but had crushed limestone sand used for a base to place stone pavers on.  This sand was very white but was much coarser than the Lowe's Pulverized limestone.  Any thought on which I can use or should I keep looking for Southdown limestone sand? <The Southdown you're looking for is Southdown tropical play sand, but this still may be the stuff. I'd try my earlier suggestion. Good luck! -Kevin> Dave from Indianapolis

Re: Calcium source If I could find Southdown or Yardright play sand in Colorado, I'd be a rich man.  I can't even get them to return my e-mail inquiries.  Do you have their phone number perhaps?  I'll bug them until they send an 18 wheeler out loaded with it.  :) <The parent company is Cemex.  The rumor around the hobby is that they will not respond (at least not favorably) to inquiries from aquarists since they supply aquarium industry companies.  I am quite sure that if you are determined and get the right person on the phone (just asking for "calcium carbonate play sand") you could arrange for a truck load to be delivered!  Be prepared for the sand to be shockingly cheap and for the trucking to cost more than the sand.  Adam>

Re: My Acrylic Aquarium Bob, Thank you for the quick reply. I have noticed in the FAQs that there are differing opinions about pre-rinsing Southdown sand, with the majority stating 'no rinsing necessary'.  Do you hold a contrary view?   <Evidently so... I would definitely wash the sand... in aliquots/portions in a "plastic pickle bucket"... about ten pounds at a time, "swishing around" with my hand, pouring off... till it ran clean/er. Try some and see.> With respect to lighting, it is my intention to initially maintain a fish only system.  I would like to provide enough light to grow/maintain the coralline algaes on the live rock.  I understood your response to say that 250w MH pendants would be adequate for this purpose. <Yes... even 175's> There are three cut-outs in the top, would you recommend one pendant over each, or attempt to spread 4-5 pendants over the 112" length of the tank? <Try three and see what you think> Your advice regarding additional external mechanical filtration is well-taken, but I am unsure how to deploy this strategy while minimizing maintenance efforts.  I understand that weekly cleaning of mechanical filters is key if meaningful nutrient export is to occur. For a system this large, a mechanical pool filter w/large pleated insert seems to be the logical choice, but would seem to introduce a cumbersome weekly cleaning ritual.  Are there better/easier options I should consider? <Yes. Please see here: http://www.wetwebmedia.com/marmechf.htm and the "Related FAQs" at top, in blue> Again, thank you.  Your advice is greatly appreciated. <Glad to offer it> It will be mid 70s and sunny in Minneapolis, today.  Think I'll sit outside and pretend I'm in San Diego....if I had this new book I'd ordered by Calfo & Fenner in my hands to read, it would be a perfect day...... <Wish you (and I) had it in hand. Bob Fenner> Steve

Sand from Home Depot Thanks,      Was also wondering if using the play sand from Home Depot is ok for my reef if I mix in some live sand, and is the white Caribbean better than the tan colored play sand, and should I stay away from silica, I notice the white Caribbean they sell says "silica free" Again, Louie <The sand that you are looking for is Aragonite sand, some Home Depots carry a type of sand called south down.  I think the white Caribbean sand may be the same stuff, but I am not sure.  I hijacked the following info from a different response on our site "There are several versions from Southdown of Caribbean aragonite sand. Some is labeled "Southdown Plays sand" and some "Playwright play sand". You are looking for Caribbean aragonite, "mined" from the Caribbean. Also, look in the Garden Dept, not the concrete dept where they will send you for sand. If the bag is from Southdown (on the back label) you can confirm the contents by calling Southdown at (800) 526-1753." We cannot get the good sand at our Home Depots out here on the west coast.  Once you get your sand you can mix in live sand to seed your sand bed, it would be best if you could get a few scoops from a friends sand bed, the addition of live rock will seed your sand bed as well.  I do not buy into the whole live sand in a bag thing.  Best Regards, Gage>

Home Depot Sand Response Previously posted:I thought I read on one of the responses that it is ok to buy play sand from Home Depot to use in your aquarium and to seed it with some live sand or live rock. Is this still ok or has it been found not be safe now or anything? <I would not use it because of the high amount of silica present, additional algae food source, and it will do nothing to help keep your pH up.> ***************** I would like to respectfully disagree with this response. The Home Depot sand that is referred to here, [which] used to be the 'SouthDown" brand, is not silica based sand. It will indeed help with keeping your pH stable. It dissolves in vinegar, silica- based sand will not do this. I used around 300 pounds of it for my tank and it has been doing wonderful for nearly 2 years now. I believe the Southdown name changed to Yardright, but I'm not sure.  You can always test it by dumping some vinegar on it.  <Thanks, Bill, but you did not mention Southdown sand, and if you were using it for nearly two years, and doing wonderful, why are you asking about it? Seems to me you've done your own homework. James (Salty Dog)><James... this gentleman was chiming in on your previous day's post... FWIW, I do agree with him... the Southdown product is almost entirely carbonaceous, very little silicate content... RMF>>

South Down Sand Dear Steven Pro, Thank you for your quick response! One Last question, today I purchased 8 bags of the Home Depot Southdown sand and once home, I noticed the following changes as underscored. Soft Texture Sterilized Silica Free Not recommended to traction or aquarium use Everything else is identical including the SKU. Are you aware of this change and should I be concerned about the statement saying that it's not recommended for aquarium use. <I have eight bags myself sitting in the garage, so I went out and looked them over for the disclaimers you have seen. Mine only say that the sand has been sterilized. The silica free statement is a good thing. I have no idea what soft texture is, but the "not for aquarium use" sounds to me like a legal disclaimer or something they added to appease the other companies that sell/market their sand. I would not worry about it. I do not remember if I mentioned it previously, but I would sift the sand. I have found pieces of quartz rock in the sand. Southdown packages a lot of other materials for landscape use and there is a possibility of other things slipping in. Again, nothing to be too worried about. The stuff is so cheap, any potential risk is far outweighed, IMO.> Thanks again, Ron Allard <You are welcome. -Steven Pro>

Make A Sand Decision Hi Bob, I wanted to get your opinion on the great sand debate. <Actually, Scott F. here today> I have read dozens of opinions on using normal play box sand from HD (by Paragon), all negative.  However, not one of these people admits to ever having tried it, they just all "know" it's bad.  Do you have direct experience with this or a similar product?  It seems ridiculous not to use it if it's actually OK and only "folklore" is stopping us.  What do you think? <Well, there may be some merit to the opinions. I personally have not used this product, but I have used the infamous "Southdown" play sand, and it works quite well. It is an Aragonitic product, and provides a lot of good benefits (calcium supplementation, proper grain size for denitrification, etc). I have heard that many regular play sand products contain a lot of impurities, ranging from metals to silicates, so what appears to be a great "bargain", could actually be an expensive mistake! Do check with the manufacturer, if possible, as they may be able to give you some idea as to the composition of the sand. Hope this helps! Scott F>

Southdown Sand While researching the availability of Southdown Play Sand I discovered this piece of information on the Southdown/YardRight web site. "Helpful Tip. Since YardRight™ Tropical Play Sand has been purified at high temperatures before packaging, be sure to add some moisture to return it to its natural state. Moist sand makes for better sandcastles. Not suitable for aquarium systems and traction purposes." Should I be concerned about this disclaimer?  Has anyone heard of problems using this in the aquarium? The link below is where my search started. http://products.crabstreetjournal.com/southdowntropicalplaysand.html <Thanks for the note, Rex.  Each one of the 60 or so bags my friends and have used in our aquariums, have this same statement printed clearly on the front of bag. Nobody I know has ever had any problems (over the course of at least two years) with the Southdown sand. -Zo> Regards, Rex Merrill

Southdown sand use? I was wondering what you folks think of south down sand for the marine aquarium. There has been a lot of raving about it on the net and in some forums. I would like to know what you thinks about it cause I am about set up a new tank and can get a real deal on 40lb. bags of it.  Happy new year, James Wesley <It's a winner! Please see here re: http://www.wetwebmedia.com/marsubstr.htm, the FAQs linked (at blue, on top), or just insert the term "Southdown" in the search tool on the homepage, index... Bob Fenner>

Southdown Sand James, I'm sorry, I wasn't clear. It wasn't my question originally. I just read it on the FAQ's yesterday and thought I'd pipe in, and share my experience with this fellow and other readers. Home Depot is the only place that carried the Southdown brand that I'm aware of. So when I read Home Depot sand, I assumed he was talking about Southdown. Sorry for the confusion.  <Bill, yes it was confusing. Apology accepted. James (Salty Dog)> <<Sheesh. RMF>>

Mystery Sand... Dear Crew, <Scott F. your Crew member tonight!> I know this topic has been covered extensively on your site and throughout the net. BUT... A fellow aquarist and I just ran into a pallet of "Yardright White Play Sand" at a local store. We've been HUNTING for Southdown substitutes all around but of course we cant find it. The bag says that it its made from marble, and we brought our "Vinegar" test kit with us and it bubbles.. so we bought some.... We both want DSBs in our new tanks. I've seen Aragamax, and its not near as white as this stuff.  Is this the right stuff????? THANKS! <Hmm...since this stuff is not aragonite based, I wonder about its buffering capabilities and level of purity, despite its apparent solubility. I'd be more inclined to pass on it for this very reason. Do check with other hobbyists to see if they have used this stuff with success, but proceed with caution. Good luck! Regards, Scott F.>

Live sand question Hi James the salty dog or whoever reads this,  <Hi Shawn> I looked over the link and asked my local fish places about it and have decided to just go with sand only. I have one last question regarding the live sand. I remember reading one response, I could've sworn it was on page one of the live sand questions and I've re-read both FAQs twice now but I can't seem to find it again. I thought I read on one of the responses that it is ok to buy play sand from home depot to use in your aquarium and to seed it with some live sand or live rock. Is this still ok or has it been found not be safe now or anything. <I would not use it because of the high amount of silica present, additional algae food source, and it will do nothing to help keep your pH up.>  Sorry one more question, the live rock I'll be getting for my tank is most likely going to be uncured and since I'll have an empty tank and I plan to cure it in the tank would it be ok to just add the sand while it's curing or should I wait till it's done curing and then add the sand?  <Problem with that is with all the die- off from the rock, it will be harder to vac the crud up with the sand being in there. James (Salty Dog)><<RMF would like to throw in a point here... HD sells both a near-pure silicate "Play Sand"  and a "Southdown" product that is almost entirely carbonaceous... there is very little silicate content in the Home Depot Southdown product... this last should work fine.>>

DSB substrate question Good morning (or maybe noon, if you're east coast), <It is now the afternoon here.> I'm building a DIY refugium with a DSB. I've seen you recommend Home Depot Southdown sand before. I went to my local Home Depot and they did not have anything by that label, but they did have "playground sand." It was sugar-fine, composed of crushed marble, taken from calcite ore. <You do not want calcite. It does not dissolve nearly as well as aragonite. There was a very good article in the October 2002 issue of Tropical Fish Hobbyist by James Fatherree discussing the differences.> It was labeled as over 99% silicate free. Is this essentially the same thing as Southdown? <It does not sound like it.> Would this work for a DSB or should I consign myself to the high prices of my LFS? <I would continue to search for a better product. There are several online vendors now selling Southdown like sand. I would also ask a local marine aquarium society. They could probably direct you to someone that sells Southdown or a similar product.> Thanks for your counsel, John <Good luck! -Steven Pro>

Local sand I was wondering if sand from a local freshwater sandpit could be used for substrate. I would seed with some live sand. It is in a 1000gal tidal pool/fuge I am constructing. Time is not an issue and I can wait for it to become live sand. Also wanting to use some local stones as rock, porous limestone type. plan to seed the rock with pods etc. will this work. it would cost a small fortune to buy from LFS or online pre- cured, etc. <If these materials are indeed calcium carbonate based you'll be fine. I would ask the folks who run the sandpit the composition of the material there... if it is more than a few percent silicate based, you would be better off seeking out another source... for reasons stated here: http://www.wetwebmedia.com/marsubstr.htm Bob Fenner>

Marine substrate Hello All I want to first say thank you for all the great info on this site.  :)  Done much research into my nitrate problem and have formulated a solution due to all the great help already posted.  Only could not find one last answer.   For my deep sand bed is it ok to use sand from an home improvement store?   <Yes... if carbonate based... steer away from silicates. Please read here: http://www.wetwebmedia.com/marsubstr.htm and on to the links at the top, till you're satisfied> Oh yeah one last one... My current substrate is of the big variety, yes I know one of the reasons for my nitrates anyway when I create my DSB can I pour the new sand over the existing substrate?  Thanks again for all your help, this site rocks Cheers Fargo <Keep reading the links... Bob Fenner>

Re: New tank setting it up (marine substrates) Hi Bob and JasonC, How was the dive? How about posting some pics? <Fine... and we do... daily> hehe.. Well I got my tank filled with saltwater from the Waikiki Aquarium for about a week now. It's a pretty good deal, you pay a one year membership, you get saltwater for free from their well which is naturally filtered, free entrance anytime they're open, and invitations to their special events. I think now is the time to put some substrate in and base rock. I was at the Home Depot looking for the infamous Southdown to no avail but they do have a 60 pound bag of sand for $2.68. Its a local product labeled "Coral", it looks pretty fine like aragonite. The LFS in my area sells aragonite for $10 per 10 pound bag. I am at an impasse here on which one to use.  <Chat with other aquarists there... test some of the inexpensive product...> The aragonite at the LFS is a little bit more finer than the coral but is more expensive. I read that coral is not really good as a substrate (something to do with nitrates?) and fine aragonite on the other hand has a problem of cementing the surface? <Both of these are "possible" shortcomings... there is huge variability in these products> I need some advice. I have read that if I am going to use fine substrate such as these, I should not lay it on too thick while other sites I've read are saying the exact opposite and saying that I should use up to 4 inches! What do you think? As always thank you for your help and Happy Holidays!.. <Please read here: http://www.wetwebmedia.com/marsubstr.htm and where the links lead you. Bob Fenner>

Alternative sand substrate Hi Mr. Fenner, I've been reading in your daily FAQs, and older FAQs from lots of people that use the Southdown play sand from Home Depot. <Yes, a dear acquaintance is quite "buff" (she) from hefting several pallets about this far to the west (California)> Unfortunately, I live in Montreal, Canada, and we do not have that brand here. Although we do have the Home Depot store chain here. <Do make inquiries... if you can get a few pet-fish friends together, perhaps a whole pallet or two can be special ordered, shipped up> They do carry the line of different types of sand of another brand that is called Quikrete. I've looked at the sands, and while they do have what they call a common blend of sand that has a warning on the label that says it contains silica in it,  <It does, in high concentration> they have another blend that is labeled for sand-boxes that has been washed, cleaned, and dried, and does not say anything on the label about any silicates in it. Have you ever heard of this brand because the company is in the States?  <This natural product is not consistent... you can look with a magnifying glass, low powered microscope to easily assess how much silicate/sand is present... the shinier, flatter, smoother "poker-chip" like pieces...> Would the fact that nothing is on the label for the play box type about silicates make it safe enough to use in a reef-tank, or it means nothing, and I would be better off not chancing it?  <Worth investigating further. Please do post your query to our: http://talk.wetwebfotos.com/ and other bulletin board, chatforums in the hobby... some folks will certainly have recent personal experience here> I figured that if this sand is catered to sand-boxes, they would know enough not to make it health hazardous for the children that will be playing in it, since the silica is a known cancerous agent. <Umm, actually... most everything is a "cancerous agent" (in point of fact our bodies are quite cancerous... not a joke)... in quantity, type of exposure... In the grand scheme, scale of things, large particles of silicon dioxide (a very common, ubiquitous component of the surface of this planet) are relatively non-toxic> I would really like to find an alternative to buying something like the CaribSea brand because around here, the cheapest I've found for CaribSea is $32.00 for 15lbs., while the Quikrete brand for instance costs $4.95 for 50lbs. What a difference in price eh!!!! <I'll say! See my comments above...> I've also looked online at the CaribSea brand, and while it is cheaper a bit, once you add in shipping etc. it comes out to the same price. I just think it is crazy to pay that high price for sand, ( while the composition of the CaribSea brand might justify the high price, I would really prefer an alternative if it would do just as well, as this hobby is expensive enough!!). <Agreed... but not for the industrious! Bob Fenner> Thanks in advance, Greg N.

Looking for a Cheap Sand Source Bob, <<JasonC here filling in while Bob is away diving.>> I'm looking for some "home-depot" cheapo sand to mix with my 30lb of live sand and live rock, I've heard that play-sand and blasting-sand have silica and are to be avoided. <<this is true>> so if you could steer my in the right direction, me and my wallet would be thankful. <<Keep your eyes peeled for the brand "Southdown" This is probably best suited for the base of deep sand beds and refugiums as it is very fine BUT... it is re-branded stuff from CaribSea [or so the rumor goes] and so Southdown is supposed to be pure aragonite. This is about the only thing at a Home Depot that I could recommend for use in a fish tank.>> thanks and happy holidays <<You are welcome, and yourself as well. Cheers, J -- >>

Marine substrate Good morning Bob, Hope you had a fun/safe 4th.  <Yes, stayed home "working"...> I almost hate to keep bringing up this same subject, but I've checked a few message boards and couldn't find an answer, (wish the WetWeb forum was up).  <Soon my friend> It's about use of the Southdown play sand as substrate again. I've been to several Home Depots looking for this stuff, but all of them carried the brand, Paragon, instead of Southdown. I was wondering if you had any experience with this Paragon brand, and knew if it was the same/similar stuff.  <Hmm, don't know... do remember being told of the Southdown not generally being shipped too far away from the source (Florida) due to economics... but also know of folks who with perseverance have bought a few pallet loads and had it delivered all the way to California... maybe a few phone calls, gathering like-minded folks together (hobbyists in a club? Local retailers?) for a semi-huge order? Bob Fenner> Again, sorry to keep coming back to this same subject. Thanks as always.

Curing LR/lighting, marine substrate on the cheap Hi Bob, Hope you had a good weekend.  <Yes my friend. Thank you. Hope yours was as well> As for your question regarding the beer, I guess that's why the came up with the slogan, "Why ask why..." :-) <oh yes> Well, as always, answers bring rise to new questions. <If they're good ones> Here's today's questions: with a new tank setup, I would really prefer to re-cure all 90lbs of LR in place in one shot. What are cons of doing it this way, versus curing two 45lb batches as you recommended?  <Really, only the added possibility/chance of "overwhelming" the system and its mechanicals... and having too much, too soon of the live part of the rock die off... Always a chance of this... but smaller batches... mixed with already cured LR... less potential> Also, I've seen various posts regarding the Southdown sand at Home Depot. Have you had anymore experience with that?  <Yes, ugh, mainly lifting bags...> In your latest responses on that subject, it didn't seem that you really had an opinion regarding its use. I'm mainly interested in the buffering capacity of the sand, (similar to coral sand?) <Hmm, almost identical... does have equivalent properties, composition... should look through, possibly screen for misc. glass and metal pieces... though I've never encountered any.> ... and the cheap price of course! Thanks again. <It is indeed a real bargain. Bob Fenner>

Substrates for marine systems Lorenzo, <Hi Thom.> I have been reading and gathering my toys to set up a 40g tank. I read about the use of Home Depot's Southland sand for the substrate. It's attraction is that it is very inexpensive (some would say cheap). Is this the tip of a new trend/product? Is this really safe to use? I am thinking of a 50/50 mix with fine aragonite about 2" deep. I would appreciate your opinions about this.  <I personally haven't tried it, but I too have head stories of it's success. Still, in my opinion, a 40 gallon tank shouldn't clean you out, trying to build a 2" sand bed from known-good aragonite... -Lorenzo> You must be a great friend to stay home and do "Bob's work" while he is in Asia doing the fun and sun thing. <<He is. Bob F.>> <Hah! Well, yeah. Bob's a good guy, and I'm excited to see what new photos he brings back...!> Thanks for your input. Thom Walters

Milky Water (marine substrates) Bob--As you recall, the unwashed Southdown I added on Sunday caused my tank to turn into a milk vat.  <Yes, we both wish you would have washed it ahead of placing> I added 90# of LR on Tuesday night--the water is starting to clear some, and I can now see about 5 or 6 inches into the tank.  I also know there is quite a bit less crud floating around in there because the alk had decreased from the initial test of 7.2 on Tuesday afternoon to 3.2 last night. Ca had decreased from 440 to 380. (I have also moved the Ca reactor from the old tank to the new tank for the cycling process.) <All predictable... Say, you don't know of someone, a shop maybe that might lend, rent you the use of a Diatom (tm, Vortex products) Filter for a day or two?> I added a makeshift power filter to the sump last night--by taking the old biofilter media from my DAS (the cylindrical shaped one) and attaching the Rio 2100 (the one that came with the Turboflotor) on top with a tube to pull water through the filter. (I had removed this biofilter from the DAS several weeks ago.) That has also seemed to help some. I'm borrowing a Magnum HOT filter from a friend tomorrow if it's still looking murky when I get home tonight. <Oh, yes, these will help... still, look for the DE filter> Since Southdown is so highly recommended on the newsgroups and many people advise against washing it, I did a search on the reefs.org site last night, as I'm sure there are plenty of other people that have had the same issue with milky water as I'm having. I found several threads that seemed to indicate that once the nitrifying bacteria get established, they will coat the tiny particles that are clouding the water and that will cause them to stick to the rest of the sand bed, clearing up the water. This would also be consistent with Mike's (at Paragon) statement that once the cycled LR is added, the water will clear up in 24-48 hours. Is this a plausible theory? <Yes... but I would still wash it... in five, ten pound batches... in a plastic (five gallon "pickle") bucket...> I tested for organics last night, 24 hours after the LR was added. Mike said I shouldn't see a spike at all because they fully cycle the LR in their tanks before it's shipped, and the packing was such that the LR was just as wet when I received it as when they pulled it from the tanks. I've confirmed from other people on the NG that they have purchased Paragon's LR and have not experienced any ammonia spike after adding it to a tank. I did get a reading of trace ammonia and nitrite last night--each equal to or less than the lightest color chip on the Salifert test kits. Nitrates tested around 2 ppm. <I wouldn't make such a "guarantee"... not anyone's control enroute can spell/determine such results...> At this point, I'd like your comments on my plan to clear up the water and make sure the tank will support denitrification. I added two cubes of frozen food this morning--if I don't get a noticeable spike from that in 3-5 days (is this enough time to tell?), then I'll conclude that the LR is doing its job and was adequately cycled such that it is able to support filtration. I also fed the tank for the reason that I believe that the added organics will help to thicken the foam in the skimmer, which should make the skimmer more efficient at pulling out the particulates that are clouding the water. <Hmm, I wouldn't "feed" the system like this... or inorganically (with ammonia compounds...)... "just" let time go by... there is sufficient organic input from the new live rock> One other question--I was also thinking that to increase the skimmer output on the new tank, I could add some of the skimmate from the old tank to the sump of the new tank. Sounds crazy, I know, but I was thinking this also might help to confirm whether there is going to be a spike, and also would help to increase the efficiency of the skimmer on the new system to speed up the clearing of the water. Does this make sense?  <It does... but I would not do this either... unnecessary, and a real chance of forestalling cycling rather than hastening it...> I haven't done this yet, as it sounds backwards to add skimmate to a clean system, and I wanted to see what you thought about it before I did it. The old tank settled down and wasn't dripping this morning--although after doing the water change on Tuesday to harvest water for the new tank, it was leaking 2-3 times faster than before, and dripping from several different places from the back. The rear seal is obviously giving way. Needless to say, I was freaking out at that point, but now it looks like it will hold if I add top off water in small amounts so as not to change the pressure dynamic on that seal too quickly at any given time. Ideally, it needs to hold for at least another week, preferably longer. <Keep the water level low... a large catchment container under it... fingers crossed... re-seal it (you know how?) when empty...> I'll keep you posted--for now the emergency situation is over, and I'm keeping a close eye on the old tank. Thanks for your thoughts again. P.S. The parrotfish pic on yesterday's FAQs is really cool--is that one of the pics from your most recent trip? <Yes, thanks for the notice... and am getting better (easy to do because I'm starting so far back on this learning curve) with the new Nikon scanner.... much more to come. Bob Fenner> James A. Deets

Re: Milky Water Thanks for the response and insight, as always. I called the LFS and they have a Magnum HOT with a diatom filter I can rent for $5 a day. I think I'll go up there in a few and pick one up today. They didn't have a Vortex Diatom filter. <"Cause I hate that milky wahtah.... Georgia, you're my home..." Not a great product/substitute, but it will do> On the "no spike from the LR" issue--just to clarify--he's not making a guarantee, just relating observations. <I understand> I'm just adding those observations to the mix of data I'm getting from my water tests in drawing conclusions about the denitrifying capacity of the system. Since I've already added some food to the system, how long should it take for it to break down into ammonia compounds? i.e., if I'm going to see any ammonia from this food breaking down, how long should it be before I see it? <Days to a couple of weeks> Luckily, I won't have to reseal the old tank. Since I only bought it a few months ago (albeit used and with no warranty), the LFS is giving me 100% on it as a trade in on the new tank. They will have the honor of pinpointing the leak and doing the resealing duty! <Very well> P.S. If I ever upgrade to (or add??) a 300 gallon system, the sand will be washed thoroughly. . . :) <I believe you! Bob Fenner>

Play sand... This is the question I am commenting on. This sand that the person is talking about is a tropical play sand packaged by Southdown, the same company that packages for CaribSea. It is the exact same stuff. It is found at Home Depot for less than $4.00 for a 50 lb. bag. Compared to $1.00 a lb. from CaribSea. Let me know if you want any more info on this. I know plenty of people that have it in their tank and it works and looks great. (it should, it is the same stuff meant for aquariums) I have a few bags on order.  Ryan QUESTION: Well this is kinda off subject, but the sand I have in my tanks now is aragonite which is about 2-3mm in size. I have read in a variety of places its better to have sugar size sand (oolite?), so animals can burrow into it.  I have also heard that there is a sand that hardware stores sell that can be used in the tank, which I'm sure is cheaper than buying it at the LFS. Have you heard of such a sand, and if so what is it called :).  Bob's Answer: Hmm, I'd like to know what this sand is at the hardware store. Most all I've ever seen are silicates (kiddie play box sand), metamorphic chondrites ("gravel" for freshwater), and maybe flints (good for some freshwater systems). None of these are good for marine aquariums.  And, nah to the finer substrates (oolithic... fine, dusty stuff) as being better. They have their own sets of problems. You're better off with the 2-3mm stuff of all about the same grade. Maybe place the sugar stuff in a refugium.  >> Am sort of aware of the sand... but still a little leery of posting much about it... but will indeed send this info. to ffexpress and the original querier... Do you screen it at all? Ever find much/any contaminants... Probably not... as it's intended for "kiddies"... Bob "the worry wart, but a real cheapskate as well" Fenner

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