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FAQs about Marine Substrates 2

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 RockBiominerals in Seawater, Understanding Calcium & Alkalinity

Related FAQs: Marine Substrates 1, 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, Southdown & Such, 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,

True grit, ala Pulau Redang, Malaysia

Moving A Sand Bed...Or Not - 08/02/05 Dear Mr. Fenner, <<EricR are here tonight.>> Yours is a wonderful site with information which has always been useful.  I'm in the process of moving my 75 gal FOWLR tank to my new home, 15 minutes away.  I read in your earlier mails that you suggest not moving the sand bed, but establishing a new sand bed seeded with some sand from the existing bed. <<Yes>> Considering that it will not take me more than an hour to move the existing sand, will you still suggest that I go with a new sand bed? As usual, your suggestion will be highly valuable. Best Regards Sumit Mumbai <<Well Sumit, the issue is not the time it takes to move the bed, but rather the physical action required to do so.  The sand bed is made up of "layers" of bacteria and micro- and macro-biota.  These life forms are designed/adapted to live at these differing depths/levels of oxygen.  When you "scoop up" the bed in to buckets for transport, you "mix" these layers causing a massive die-off of much of the life within the sand bed, thus creating a pollution problem when placed back in the tank.  For this reason I think it's in your best interest to start again with new sand "seeded" from the old bed.  Regards, EricR>>

Rubble Rock 8/2/05 I am in the final stages of setting up my 180 gallon FOWLR tank and saw rubble rock at a local aquarium store.  I was thinking this would possibly be good to put in a refugium, What are your thoughts.  If you feel it a good idea can you give me recommendations on how thick the layer should be, lighting, circulation, etc. - D’Wayne <Hi D'Wayne! Thanks for your inquiry, regarding the rubble rock -  it would be just fine to use in your refugium. Keeping a fine grain 3-6" sandbed in the fuge and/or several pounds of rubble live rock is all you need. Depending on your set-up goals, lighting can be used or deleted from the set-up all together. Please feel free to do a search regarding refugium set-ups here. Tons of info, you'll be pleased D'Wayne... - Ali>

Adding more live rock, sandbed and tank Renovation. 7/31/05 Hello again, <Hey Frank!> Ali, I wanted to say thank you for the quick reply! I have a follow up question. I will be following your recommendations to replace the substrate with a 4 - 6" deep sand bed. It looks like the sand you recommended is a 1 to 2 mm grain size. I have heard a lot of opinions on .2 to 1mm sand vs. 1 to 2mm sand. Do you think you might be able to give me your opinion on the different grain sizes and why you recommended the grain size / sand that you did. <Go with the .5-1mm grain sized sand. CaribSea Aragamax Oolitic Select Reef Sand is pretty much the ideal sand for deep sand beds. Several vendors including most 'local reef stores' carry this very popular sand. You have two options here: 1. Siphon out all of your crushed coral substrate, put all live stock in bins, drain the tank, add sand bed, SLOWLY refill tank causing minimal disturbance, wait until the tank is totally clear then proceed to add live stock after careful acclimation. 2. Siphon out apprx. 90% of your crushed coral, leaving just a 1/4-1/8" bed, (covering just the bottom of the tank for aesthetic purposes) and plumbing in an additional sand filter to your tank. For example, a 40 gallon breeder with a 4-6" sandbed plumbed into your existing sump.   Option #2 will be much less work and stress on the animals, however it will require an additional tank (taking up space). On the bright side, you'll be able to keep your nitrate levels in check and the 40 gallon side tank will act as a fully functional refugium as well.> Thank you, Frank <No problem Frank, good luck with the tank renovation. It'll require some careful planning and hard work, however it'll be worth it in the long run. Bust out some cold brewskis and get to work! :) Ali>

Oyster shell filtration 7/4/05 Dear crew, <Mark>   Thanks for all the useful information on your site.  I have started a new 46 gallon saltwater tank that has been up for 4 months. I have 2x65 pc lighting which I am going to upgrade soon. In the beginning I had  1/2 bio balls and 1/2 coral shells in my sump with live sand and macro algae.     I recently bought some oysters to eat and came up with the Idea of using the shells upside down in my sump. I double boiled them and cleaned them and began to place them upside down in my sump, using live sand in the cup of the shell. It is a big guess of course but the way the water flowed from the wavy tips of the shell into the belly of the next seemed that it would work really well. And it only took me out about 4 bucks for the shells and a meal. But now I only seem to be growing the hard green algae. I would like to have a little more of the kind a purple tang could eat, as I am going to get one when I feel my tank is ready. The rest of my set up is (1 false Perc and seabae,1 coral beauty, 1 mandarin, 1 diamond watchman goby, 10 snails, 6 hermits 30 pounds of live rock and a 200.00 skimmer.) I am also using the sump inlet area as a sort of staging area for Caulerpa and copepods I have purchased for my mandarin. Any advice? <... have used Oyster shells... fresh and processed (mainly for chicken supplement)... not very soluble useful compounds for saltwater... Coverage on how to grow purposeful macroalgae and the fish you list above is archived on WWM. Bob Fenner>

Substrate question Fond greetings to all of you at WWM <and kind regards to you my friend> Sincerely hope everyone had a great holiday with good food, good drink and most of all family and friends.  <and you as well <smile>. In fact, we haven't stopped... Steve and I out to sunny California to visit our good friend Bob. A great feast and fellowship planned for tonight> Anthony, thank you for your very prompt reply several days ago regarding my question on a used protein skimmer. I've decided to opt for an AquaC EV 180, rated for tanks up to 150 gallons. <outstanding... you will not be disappointed> Now, I have a question about substrates. I did a search on the WWM site looking for the answer but couldn't find exactly what I wanted. In one of the articles about setting up a marine reef tank, Mr. Fenner wrote, "Calcite with magnesium impurities. Coral sand, crushed oyster and coral rock. These are the most suitable media and buffers. Size (2-5mm), shape (spherical), grading (all the same), and circulation (2+ gsfm, the more the merrier) have been gone over under properties." My question: Is Mr. Fenner saying one can use coral sand OR crushed oyster and coral rock OR a combination of all three. Could I mix up all 3 types to use as a substrate?  <not recommended... each/some have advantages over others. All are calcium carbonate... some calcite (crushed coral, shell)...some aragonite (best IMO for buffering)> 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> that you recommend that I can tell my LFS person to get in case he doesn't already have it on hand. I looked around on the internet, but a lot of places don't tell you the properties of the substrates they sell. I did look at Custom Aquatic, Kent Marine (their Biosediment looks like it might fit the bill), Eco System's Miracle Mud, <I'm not impressed with the latter two regarding value for price paid. You literally need to be paying mere tens of cents per pound> and Kordon Aquarium. Problem is, I just don't know which one to choose. The tank I'm setting up will be a 140 gallon with no UG filter (unless that's necessary); the AquaC skimmer, Tidepool 2, a Mag Drive 7 and Mag Drive 5 and JBJ lights. I plan on adding 75 to 100 lbs. of live rock or more if needed and, after 4 to 6 weeks (if all goes well), I'll begin adding some live corals (but no SPS corals or clams as you cautioned against that due to the lighting).  <and do be sure to hold off on putting any coral or livestock in until most all live rock is in. Any added later must be cured at home (never trust any shipped rock to be cured)> Then I'll introduce (after dipping/QT) 1 to 2 fish a month, some scavengers, cleaners, etc. Many thanks for the awesome site and the equally awesome advice! Diane (down in the Louisiana bayous and still eagerly waiting for delivery of the CMA book) <best regards, Anthony>

Thermometers & Substrate I have 2 questions for you all today 1. which is better as far as thermometers go the glass ones that go inside the tank or the sticky ones that go on the outside? <IMO, the glass ones are better, but should not be allowed to float around in the tank waiting to get broken.> 2. When I bought my substrate (crushed coral) the guy at Elmer's LFS said NOT to rinse it, but the bags say to do a light rinse. <Crushed coral needs rinsed like crazy.> Which is right? <Are you sure you have crushed coral though. Being from Pittsburgh and knowing Elmer's, I am not sure they carry crushed coral anymore. They do have various grades of sand, some larger than others.> It is not live sand. Thanks, Colleen Pittsburgh, PA <By the way, did you make Bob's pitch at Elmer's on Saturday morning? -Steven Pro>

To Rinse or not to Rinse III Ok I'm home now have set up the tank did rinse the substrate and the bags did say "aragonite grade crushed coral" there is like tiny shells and stuff in it. Not sand for sure. With three bags the base is about 1" in my 75 gal tank. Everything is up and running figure I'll let it go till tomorrow and take more salt readings and pH and then decide what I'm going to do next a little damsel or 2 or just some live rock not really sure yet. ~Colleen <I would strongly suggest the live rock cycling method. You can read more about this on WWM. -Steven Pro>

Maintenance Questions Pretty new to the aquarium hobby, but have been at it about 8 months now. Was told to wait a while before I vacuum the substrate, so I have. Now, I realize that when I try to vacuum the base of the tank, all of my live sand goes into the hose/snake as well. <Mmm, give it a preliminary stir with a wood or plastic dowel (to break up the chunks!) and devise or buy a siphon with an "exploded end" (we used to make our own out of plastic bottles with the bottom cut off and a good length of tubing attached to the narrow end...). Such "funnels" allow you to stir up the bottom, remove the muck, but leave the substrate behind> Looking for a trick to avoid this from happening. Was also wondering how long I should wait before I change the white and blue pad in my canister filter. (the water is still crystal clear, I believe due to the protein skimmer) <Do this on at least a weekly basis... good to remove the grunge there before it dissolves, returns nutrients to the water... fueling algae growth et. al.> Love the web site. Thanks, Tim Gauen <Thank you, Bob Fenner>

Maintenance Questions Pretty new to the aquarium hobby, but have been at it about 8 months now. Was told to wait a while before I vacuum the substrate, so I have. Now, I realize that when I try to vacuum the base of the tank, all of my live sand goes into the hose/snake as well. Looking for a trick to avoid this from happening. <If you have a DSB, you should not need to gravel siphon it. Occasionally some detritus might settle there, but you should not insert the siphon into the sand.> Was also wondering how long I should wait before I change the white and blue pad in my canister filter. The water is still crystal clear, I believe due to the protein skimmer. <Depends on the brand and model, but generally every 1-3 months.> Love the web site. Thanks, Tim Gauen <You are welcome. -Steven Pro>

The Opinion of Aquatic Experts Hello WWM Crew, I have a couple of questions. Is it true that you should not have a big bed of aragonite? I have 270 lbs of Aragonite in my 180 gallon tank and have been told by 2 different people that I should remove it and replace it with crushed coral since the Aragonite will turn into a mush and retain all sorts of nasty things. <Definitely not what I would do. I prefer to use a deep sand bed, 4" or more of fine aragonite sand.> The other thing they said is that I should not run the skimmer 24 X 7 that I should only run it a couple times a week or that otherwise the LR won't get the nutrients that it needs, this was told to me by two supposedly "Aquatic Experts". Is this true or are they just out of their minds? <I strongly disagree on both counts. Do not just blindly follow my opinion or recommendations. Get the advise of others. Read books, magazines, and online chat forums to formulate your own educated opinion.> Once again thanks. <You are welcome. -Steven Pro>

Silica in my puffer tank Hi ..I have a new Tank (4 weeks after maturing) and I have 3 puffers in there...before I knew any different I used tap water and that has resulted in horrible brown water ..I have since moved on to RO water .. although reassures it will not hurt my cherished puffers I wondered if there was anything we can do top speed up the process of getting rid of the silica ..we have a poly filter and have put carbon into the filter .. thanks a lot Steve <Mmm, there are a few things... some chemical filtrants, using other organisms to take up the silicate... but I would just wait... time and regular maintenance will resolve/solve this issue best. Bob Fenner>

Substrate Questions Bob, If indeed it is you today :) <Nope, Steven in today.> I am about to setup my refugium....I started a new 180 tank with new substrate Aragamax Select and this time only put 2 inches as apposed to the 4 inches that was in the old 108 tank <Better to pick either a DSB or a thin for looks only layer (less than 1").> the reason is I want to put the DSB in the refugium which will be pretty small...about 25 gallons ( I also have a sump) I know people seed new tanks with substrate from existing tanks.... and it was recommended NOT to use the old substrate (can't remember the reason) so I was wondering...Can I take the substrate out of the old tank (which is still running) and transfer it to the refugium, at least? <Sure> Should I bother seeding the new tanks substrate... <Of course!> You see I am worried that after only a week of being setup if I transfer all the inhabitants, coral and fish, they will die since the new tank has not cycled... which I have not choice to do... (you see the old tank is still in my old apartment and the new one in my new house.) <If you are using all new liverock too, yes best to wait. If you are moving all that at the same time with the fish and corals, no real big problems if done right and fast enough. You will want to watch for any ammonia spikes, but if they occur, they should be small.> So those are my questions.....Transfer substrate to refugium? <Yes> Seed either or both? <Both> How deep in such a small refugium? depend in grain size? <Over 4" of very fine sand.> Thanks for your help, Regards, Robert <You are welcome. -Steven Pro>

Substrate Questions Follow-up Thanks Steve... <You are welcome.> Yes I am moving 173lbs of live rock...I am moving a bit of an algae problem...even bought 150 snails but they keep getting eaten so now the plan is to move 99% of my hermits (the killers) to the refugium and keep just the tiniest ones in the main, and add about 200 snails. How does that sound? <Like a very good plan. I personally do not use many hermit crabs. I just do not trust them. I will use a few scarlet reef hermits.> The current 180 has 440 of VHO's. The new has 2x250W 6500 MH's and 1x250W 10000 MH with 2x165W Actinics coming on in stages... total peak is 1080W which is more than double the 440W... Keeping in mind I have to move the corals and fish within one week...Any advice to reduce shock to life forms? <Yes, use a lot of screening to cut back on the lighting. Anthony and I have both described the process in other FAQ's. Use multiple layers of window screen to shade the tank to the approximate light level on the old lights. Then remove one layer of screen every few weeks until all layers removed.> Thanks again for the great info....Robert <You are welcome. -Steven Pro>

Cleaning decor/replacing substrate You guys are doing a stellar job as always.  <Thanks kindly!> The time has come to change the crushed coral bed in my 72gal aquarium. I keep getting hair algae and believe it is due to waste and uneaten food buildup.  <especially if deep, such course media can be a nutrient trap/sink. Indeed requiring frequent gravel siphoning and very strong water movement in the display> I was wondering if I change the bed all at once or in stages,  <stages if it is used biologically (UG/substrate filter)... else all at once is possible. Do monitor water chemistry closely either way for a week or two afterwards and be prepared to do extra water changes> and whether straining, bleaching, and rinsing it is a viable alternative to purchasing new crushed coral? I'm tight on money and every bit helps at this point. Thank you, <really not worthwhile to reuse in this application. However, if the bed is static and aesthetics only it can and should be very thin (1/2 or less).> Mark Hill <best regards, Anthony>

Reef Set-up Question... Sand Making Tank Cloudy Hi Guys, Thanks so much for all the information available in the FAQ's. It's worth it's weight in gold. My set up will be.. 72 AGA Bow front 4 65watt PC Florescent, 2 10k, 2 blue 2 50/50 URI 48" 40 watt Fluorescent 100lbs fine aragonite sand 100lbs Fiji live rock (Walt Smith) 600 gal/hr overflow MAG 7 in sump pump Turboflotor 1000 in sump skimmer. My question is this. After rinsing and rinsing and rinsing and rinsing the sand again. When can I expect the water cloudiness to disappear? I am currently running a Magnum HOT with the 8 micron paper filter. It seems to have little effect. Will these small particles eventually dissolve? Or would you suggest I drain the tank and start rinsing again? <Generally, tanks clear in a matter of days. I have found that sometimes rinsing the sand makes the cloudiness worse. I would just wait it out at this point. The Hot Magnum is a good idea.> Thanks again for all you do for the hobby/habit. Dan <You are welcome. -Steven Pro>

Non-sand bed thickness ?? I have a 29 gal salt aquarium with ~ 3 inches of crushed Florida coral.  <Yikes!!! A scary detritus trap... any dreadful algae growth in the tank because of this nutrient sink?> Most of the pieces I can see are fairly large coral or whole snail shells that average 1/8" to 1/4" across. I have read on some of your other FAQs that using between 1-4 inches of sand bed depth may cause long-term problems. Is this also true of the coarser substrates like mine? <especially true of coarse substrates!> I would also like to adapt my substrate for NNR. Would adding 1-2 inches of fine aragonite substrate work with the existing crushed coral underneath, or should I look at replacing the CC.  <alas... mixed grain sizes are problematic. NNR with a deep bed of sugar fine sand. 5+inches gets my vote> BTW, I just started a 10 gal refugium with 20 lbs of live sand, 3 lbs of live sump rock, and some Caulerpa. Is it still worth the effort/expense of trying to set up NNR in my main tank's substrate? <likely yes... most display tank bio-loads can burden a 10 gallon refugium no matter how efficient it is> Thanks, Darrell <Always welcome my friend. Anthony Calfo>

Switching to a Sand Bed Hello, I have read through so much on your site and I am still in search for my answer. Great site though. I am wanting to switch from crushed coral to a sand bed. I am currently using crushed coral and an undergravel filter. I have read that you can put a screen on the crushed coral and put sand on top. <A truly horrible idea. I have seen it done once with disastrous results.> I want to completely remove the crushed coral <Yes, much better to start from scratch and build/create a DSB versus converting an UG into a sand bed.> but I am unsure of how to set up my power heads to create water movement. <Many models have clips that allow them to hang from the tank trim. Other use suction cups to cling to the glass, not as good.> I will not be able to use the tubes they are currently in because they will suck the sand up. Do I get rid of the power heads and is there something else to use for this? <If you have a sump, you can use a larger return pump. If not, you may want to consider adding one with your DSB project.> Any suggestions will help. <Do you have a quarantine tank? Can you relocate your fish to that tank? Getting rid of the UG is going to take sometime to develop a different source of nitrifying bacteria. Much to think about, discuss here. Do read as much as possible about where you want your tank to go, what direction, FOWLR, reef, etc.> Also I have seen DIY sites that run pvc pipe under the sand bed. What is the reason of this and would it be beneficial to do so? <Some use PVC in creating a plenum, as in Dr. Jaubert's methodology.> Thanks, Jass <You are welcome. -Steven Pro>

Switching to a Sand Bed II Thanks for the fast response. <You are welcome.> I am heading towards a reef aquarium. I once had quite a bit of corals but an unfortunate accident happened and killed all of them along with most of my fish. <Sorry to hear about that.> At the moment, the only coral I have is a frogspawn. I am waiting to add anymore till after my switch to the live sand. I don't have a sump right now but I would like to add one soon. My tank is a 50 gallon and I also have a 40 that is not in use at this time. I plan to move everything to the 40 while I convert. <Good plan. Do establish some biological filtration that is easily movable, a canister filter if you have one or simple sponge filters work well.> The power heads I have are the suction cup type. My concerns were that without the tubing could this suck a fish or anything to it. <A simple trick is to put a Bioball onto the intake. This acts as an extra screen to keep small fish and snails out of harms way.> Sounds like I just need to get rid of this suction cup type and get something else. <See if you cannot make these work for your application first. I hate to waste stuff. Even using the suction cups and plastic wire ties to keep the pump from falling down and blowing sand all of the place would work. -Steven Pro> Thanks

How much crushed coral? Hi Bob, <Steven Pro in this evening.> I am addicted to this site. I can't get enough! The more I read the more questions I have. My latest question is in regard to the substrate. I have a 20gal tall FO salt tank and I am slowly converting to more inverts. I have a Fluval 204 with carbon, power head for water movement and adding a Prizm skimmer. The first thing I want to do is add LR. I am going to be adding about 5lbs a week with a total of about 20lbs. Is this ok? <As long as it is fully cured, it is ok. Do not trust any mail-order liverock as being fully cured. Archive the WWM site on liverock for additional info.> Also I have about 3 inches of fine crushed coral as a bio bed with nothing underneath. I was thinking of taking it down to about 1 inch and relying on the LR for most of the bio filtration. I figured with less substrate the easier to keep clean and less likely for waste to gather. I want to be able to set up my LR so I don't have to do much moving when cleaning the substrate. What do you think? -Shaun Nelson <I would take the crushed coral down even farther, to perhaps 1/2". A thin layer of crushed coral is good for pods, but does tend to collect detritus. You may want to raise your liverock up off of the substrate by using sections of PVC pipe or lift-tubes or something else to allow for easy of water movement and cleaning. -Steven Pro>

Sand Preference I'm working on going to a deep sand bed. Quick question. If I go to 4" or so for the deep sand bed, is it better to use Carib-sea Seaflor (about 1mm) particle size, or the oolitic Aragamax (0.3-1mm)? <I have some of the Carib-Sea Special Reef Grade stuff and do not like it. I much prefer their Aragamax product.> Will the smaller grain size be too easy to disturb with high current flow flowing through the tank (12x). <Not unless directed down at the sand. I have never had a problem with it and many of the tanks I setup have flow rates approaching 20X per hour.> This is for a fish w/ LR system. Just not sure what the better substrate is. I would figure the Seaflor product since its been out longer and I've used it in the past. Not sure if the sand would be just too fine. Any insight would be appreciated. -Jim <The larger grain size tends to allow detritus to settle between the sand particles and requires regular vacuuming to keep clean. Also, I had have a terrible time getting anything to grow in it. I have inoculated it many times with various worms, many starfish, and pods and they do not do well. -Steven Pro>

Substrate Follow-up With all due respect Steve, I just want to question your advice on using the 4" substrate of aragonite in my particular setup. This is going to be a large fish only tank. I do not plan on keeping any small invertebrates or fishes used for stirring up the surface of the substrate, (in order to create the denitrifying aerobic bacteria). <You don't really need any small fish to stir your sand. Most of this can be effectively accomplished by the tiny critters that make the DSB their home; bristleworms, Chitons, amphipods, copepods, spaghetti worms, etc. I merely mentioned the DSB possibility because you referred to eliminating nitrates in your question about substrate options. I thought that was where you were going.> Shouldn't I just use a very thin layer of aragonite to avoid any problems? <A thin layer will be fine. -Steven Pro>

Substrate Questions Hi again, and thanks for the excellent advice as usual! I have another question about the type of substrate to use for my new 180 gallon fish only tank. I prefer to use a very thin layer of sand grade for the substrate instead of a course coral substrate based mostly on what I was reading in the WWM FAQ's. I noticed someone stated course substrate is harder to maintain, more detritus and "bugs" can develop in the substrate. Is this true? <All three are true, the first two are disadvantages, the last part about bugs is a good thing.> I was told be someone else not to use sand for a fish only tank, not sure exactly why. <Bare bottom tanks are very easy to clean, but can be ugly.> I have a good protein skimmer, (DAS BX-1) and it appears to be working fine now on my smaller tank in keeping the nitrates down, (around 15-20p) . My intent is to keep the nitrates really low and eliminate much of the extra debris / detritus that develops on the bottom of the tank. If sand is ok, how deep should the bed be? <For good denitrification and no settled detritus, use a 4" sand bed of fine sugar size aragonite.> Any suggestions would be great! <Have a nice night. -Steven Pro>

Ugly Sand! Hello guys! Please tell me what to do about my ugly sand in my reef tank. It's always full of brown and green algae, you know, the type that blows in the current.  <easy to control by aggressive protein skimming (daily dark product) and more careful nutrient control (no overfeeding, stocking), etc> I stir it up only to have it return hours later.  <this tends to STIMULATE more algae growth. Siphon it out or starve it out (skimming)> Cutting back the lights helps a bit,  <that only treats the symptom and not the problem... you need better control of nutrient export processes> but I thinks it's not a very good solution.  <you are wise/intuitive> I was at www.garf.org and they have a 'product' called, "Reef Janitors". You can purchase a few hundred 'crawly things' to add to your soil to supposedly make the overall environment a better one. This makes perfect sense to me, but I am a beginner into this reef hobby. My tank is 55g. with 60lbs LR and 3 inched of sand. It's been up for 8 months. Thank you!!! Pam <Pam, better water movement (to keep detritus in suspension) and better skimming may be all that is necessary. 2-3 weeks of good daily skimmate and its gone... trust me <wink>. Anthony Calfo>

Sand  I just need a small amount of sand for the bottom of a 20gl tank. My LFS only has bags of it in 30lb. increments and it's very expensive. Is it ok to just get some sand off the beach or within the first few feet of the shoreline and really rinse it thoroughly or would it be polluted and unusable? Thank you. <Please read here: http://www.wetwebmedia.com/livesand.htm and the associated, linked FAQs. There are other companies that will sell, send you smaller amounts including just a few pounds of "safe" LS to seed your system. These are linked on our sites. Bob Fenner> Elizabeth K. Birdwell

Anaerobic sand Dear Bob Anthony Steven <we three are now melded into one being... unfortunately, two of us didn't know about the severity of the problem with flatulence that the third one has...ahem. Nonetheless, Anthony Calfo in your service><<I want a shrubbery! Bob F>> I have two issues for you today if you will. Anthony, I took your advice about six weeks or so and began emptying out the cup in my Remora skimmer daily. Output kicked up immediately. Coincidentally, the Rio pump on it died about the same time, and I replaced it with a MJ1200. I am truly pumping slime now!  <outstanding> As yet I have seen no improvement in the underlying problem, however. That is a "blanket" of algae on top of the DSB, mostly surrounding my (thriving 18-month) Heteractis malu.  <yes...many times the dissolved nutrient level without a daily performing skimmer concentrates to great levels after months or even years. Especially then, it will take more than few weeks with a weaker skimmer to catch up. Increased water flow in the tank will help too> Now other real algae issues in the tank. I clean some of the same golden jelly-like algae off my glass twice a week. At the advice of my usually-reliable LFS, I added about 48 (yeah, 4 dozen) Nassarius (sp?) snails about a month ago.  <For cleaning diatoms off of glass?!?> (Some reading has since disclosed that this is two or three times what my 55 gal tank with 65 lb LR should sustain, but so far they seem to be doing all right. A-a-r-g-h!) Scum blanket is unchanged. <sure...its like putting a platter full of filet mignon in a room full of vegetarians> The second issue flows from two black areas in the DSB.. The larger is about 4 square inches and growing. Both start about one inch below the sand surface. A few days ago I got a whiff of sulfur off the water surface. My LFS says this is just evidence that the DSB is doing its denitrification thing properly, but I have my doubts.  <You are right to trust your doubts> The tank is 2 years old, but I only put in the DSB about 6 months ago. Basic parameters have always been excellent - - zero NOx’s and phosphates, pH 8.3. Calcium and alkalinity have always been a struggle (currently 310 and 8.0).  <Is the sand deep enough? over 3" is minimum necessary... over 5" would be ideal. If you are under three inches, then I'm not surprised. Aerobic pockets are rare in tanks with adequate circulation, but this combines with the presence of blanket algae on the substrate is prime evidence that there are dead spots of water flow at the bottom of the aquarium. Sounds like you need to add or adjust water flow> The tank is lightly populated, with only 4 smallish fish and 6 modest-sized soft corals. Everybody is healthy, although I think my hammer coral would like more calcium. How much trouble am I in with the black spots? <very little risk...it bubbles off easily. But do correct and prevent from more occurring> Best regards and thanks for all your help. Newt <always welcome. Anthony>

Anaerobic sand II Thanks, Anthony.  <always welcome, my friend> The sand bed is a solid 5 inches deep.  <outstanding> The theory behind the flock o' snails was that they would disturb the surface of the sand and thereby disrupt the algae growth through mechanical (as opposed to digestive) processes. In practice, they all jump out of the sand when they smell food, then dig in an hour later. A few venture onto the glass at night. <I see the logic, but would recommend better water movement to keep detritus in suspension for export by filters/skimmers as a better means to this end> I have about 1000 gallons per hour flowing through the 55 gal tank (the skimmer/MJ1200. a Marineland 400 sans BioWheel, a Fluval canister sans biomedia, a separate MJ1200, and a big PowerSweep power filter), but most of it is in the top 8 inches of water.  <exactly... and a common mistake that I have executed myself as well. You do indeed have a lot of great hardware for movement... just adjust and tweak until the slow or dead spots are reduced> If I read your advice right, I will redirect one of the power filters toward and across the sand surface where the black spots are forming. Anything else I need to do to counteract the anaerobic action & sulfur production? <you are correct. And the diffusive action of the water movement is usually all one needs. It is indeed possible to have measurable different zones of water chemistry from great movement atop and weak movement by the substrate.. oxygen and pH readings can be quite different from near the bottom when compared to the top in such aquaria... amazing but true> Since I wrote, I added a colony of Zoanthids about the size of a lemon, and skimmer production leaped to about 12 ounces of light, cloudy skimmate a day. I assume the coral and (more likely) underlying rock were not fully cured and will work themselves clean in a couple of weeks. <quite possible... throttle back the air or water in the meantime to yield darker skimmate> Thanks again, Newt <best regards, Anthony>

Sand clumping I'm currently using live sand as my substrate and I went away on vacation and noticed when I came home my sand was clumping up into little balls. Is this something in its early stage or just because I didn't stir the top of the sand. <no... sign of a significant pH change... a sudden and severe drop in pH when you were away (as in nighttime without Kalkwasser to keep it up... or buffer by day to do the same)...OR... the sudden addition of Kalkwasser to much or too fast. Kindly, Anthony>

Silicate based sand Robert, I'm looking into silicate based sands for my marine FOWLR tank. The only reason is that I can fill my 80 gallon long with 3 to 4 inches of sand for $5 versus the $200 for any of the local aragonite sand. Some people say this is fine. Others say it isn't. I realize that with silicate based sands I'd get no PH buffer and I could have a problem with nuisance algae. Then again, I've also read that the algae won't be any more of a problem than with aragonite sand. I can seed the sand with GARF grunge (I live about 5 miles from GARF so that's not an issue at all) but I'm curious to know if there is any reason silicate sand wouldn't make a good live sand bed. Any thoughts? I'll probably get the aragonite anyway, but I'm just really curious. <Please read here: http://www.wetwebmedia.com/marsubstr.htm  I would not use a silicate based substrate in nearly all types of marine set-ups... for the reasons you have listed above and others in the article cited. Bob Fenner> David Rencher

Re: Silicate based sand Oh, you mean I could have just read the website for the answer? DOH! How silly of me to forget. Thanks <Thank you my friend. Be chatting. Bob F>

Advice needed (marine substrates) Hello guys, <Hello> Let me start this off with the obligatory "Thank you ever so much" for the resources your team makes available for us hobbyists struggling to make a nice home for our pets. Without the dedication and information you provide, there would be much more people turning away from the hobby. I'm also a big fan of CMA. Looking forward to more publications! <Me too> Now to the bones of my question, I'm in the process of setting up a 46 gallon reef. I've tried many approaches in the past 15 years, and have decided to stick with what I have had great success in - good rock, good sandbed, and careful feeding. <All good inputs> My question is this: I've just purchased equal portions of oolithic and special reef substrate from CaribSea (60lbs total). My plans are to keep the special up front on top of a 1" layer of the oolith, and around the base of the live rock, and to build up the oolitic sand toward the back. Reason for this, I'm hoping to allow detritus to be swept out of the back area and to settle up front in the coarser aragonite. I'm thinking this will be much easier to clean minor build-ups and allow a place for the tiny zooplankton to settle in and work on the material. I'm not too sure what the final depth will be, but I'm aiming for 3" and the tank will be lightly stocked and fed, with brisk water movement and as much live rock off the bottom as possible. Eventually, as money permits, I will also be going with a sump/refugium. <All right> What concerns or problems going with this should I be aware of down the road? Would it be better just to put all the oolitic on the bottom with special on top? I do like the way the finer sand "shimmers" when on the surface, but am willing to compromise for the sake of the tenants. (Eventually to become a home for a pygmy flame angel, a hippo tang, a Jawfish, some cleaner shrimp, and a few other candidates I'm still researching) Your assistance is greatly appreciated, and a big thanks in advance! Sincerely, Mike from Texas. <Well... Anthony and Steven would/will assuredly answer differently. I say to go ahead with your plan above as you state it... and see how all develops... there are many "different" experiences with mixing grades of marine substrates, sloping them... mainly a mixing in time, settling to one overall level... some chance of anaerobic challenges (not much IMO/E)... Again, I say dang the torpedoes, full-speed ahead... But will leave your message here for the boys response as well. Be chatting, Bob Fenner>

Advice needed (Steve's input) Hello guys, <Steven Pro this afternoon.> Let me start this off with the obligatory "Thank you ever so much" for the resources your team makes available for us hobbyists struggling to make a nice home for our pets. Without the dedication and information you provide, there would be much more people turning away from the hobby. I'm also a big fan of CMA. Looking forward to more publications! <Glad to hear it.> Now to the bones of my question, I'm in the process of setting up a 46 gallon reef. I've tried many approaches in the past 15 years, and have decided to stick with what I have had great success in - good rock, good sandbed, and careful feeding. <All good ideas.> My question is this: I've just purchased equal portions of oolitic and special reef substrate from CaribSea (60lbs total). My plans are to keep the special up front on top of a 1" layer of the oolitic, and around the base of the live rock, and to build up the oolitic sand toward the back. Reason for this, I'm hoping to allow detritus to be swept out of the back area and to settle up front in the coarser aragonite. I'm thinking this will be much easier to clean minor build-ups and allow a place for the tiny zooplankton to settle in and work on the material. I'm not too sure what the final depth will be, but I'm aiming for 3" and the tank will be lightly stocked and fed, with brisk water movement and as much live rock off the bottom as possible. Eventually, as money permits, I will also be going with a sump/refugium. What concerns or problems going with this should I be aware of down the road? <I have the special reef grade sand in my current 55 gallon reef and do not plan to use it again in the future. I have had a difficult time getting a lot of critters to live in it. I think it is a little too coarse for most. Also, it traps too much detritus.> Would it be better just to put all the oolitic on the bottom with special on top? <The reverse would be better.> I do like the way the finer sand "shimmers" when on the surface, but am willing to compromise for the sake of the tenants. (Eventually to become a home for a pygmy flame angel, a hippo tang, a Jawfish, some cleaner shrimp, and a few other candidates I'm still researching) <I would probably mix the two together and get more oolithic sand to make at least four inches of uniform depth.> Your assistance is greatly appreciated, and a big thanks in advance! Sincerely, Mike from Texas. <You are welcome. -Steven Pro>

Re: Advice needed (marine substrates) Perhaps "building up" was an improper choice of words on my part, my apologies. See if the attached picture makes what I'm trying to convey clearer. I'm aiming for a completely flat bed with even depth, and "sloping" the mixture of the two grades. The proportions in the picture aren't, of course, exact. I am thinking about using more reef special than sand overall. Thanks again for the knowledgeable input! Mike <I understand better what you wish to do, but I still would not do it. Sorry, but it is better not to trap detritus in the sand at all if possible. Far better to remove from the system by keeping in suspension with vigorous circulation, no dead spots or areas for settlement, and various methods of filtration. -Steven Pro>

Re: Advice needed Excellent points, Steven - Thanks! <I have the special reef grade sand in my current 55 gallon reef and do not plan to use it again in the future. I have had a difficult time getting a lot of critters to live in it. I think it is a little too coarse for most. Also, it traps too much detritus.> I have noticed that most worm life in my previous setup (especially the nest of spaghetti worms) seemed to prefer living in the finer sand, but the amphipods and copepods readily infested the coarser areas. <<Yes, this is true. Most of my pods are on/in the liverock.>> As for the detritus, I was hoping in by keeping the special up front, to concentrate and slowly siphon it off during normal maintenance. <<Better for it not to be able to get trapped at all and end up staying in suspension and caught in various filters.>> <I would probably mix the two together and get more oolithic sand to make at least four inches of uniform depth.> I am considering this, however I do want to provide as many distinct areas of substrate to accommodate different organisms. Will equal parts of mixing the two be a hindrance in keeping a flourishing supply of 'pods and complicate a jawfish's efforts to build a burrow? <<I would not use equal parts. I would put an emphasis on the fine sand to fill in between the large particle size sand.> I'm thinking the finer sand will just infuriate him by collapsing. <<The large parts mixed in should give him a good consistency to work with.>> That was another reason I had for moving the bulk of special up front so I can more easily keep an eye on him. <<Our pets have a mind of their own. You can encourage him to do certain things, but do not get too bummed out when he does the opposite.>> Again, thanks for all the great input! Your fan, Mike <Wow, a fan! Thank you very much! -Steven Pro>

One more add on question (marine substrate depth...) What is the depth of sand substrate you recommend?? With our sixty lbs of bioactive aragonite reef sand we have about 1 inch. Should we add more??? <Less than 1" or greater than 4".> We're planning on a fish and invert. system and our next addition will be live rock in a few days/weeks. Again, thanks again for your help!! Katie <You are welcome. -Steven Pro>

CLEANING CRUSHED CORAL SUBSTRATE!!!! Dear Robert, <Steven Pro this evening.> I'm so glad I found your site. I hope you can help me with my new cichlid tank set up. Though I cleaned 40 lbs. of crushed coral the best I could, once it was in my tank with water (46 gallon) it still seems to be very dirty as the tank has been white and cloudy for a couple of days and each time I move around the substrate, it kicks up more and more white dust to cloud the tank. I have an Eheim canister filter attached #2217 and am using a Power Clear power head #402 for water movement.. Is the clouding eventually going to go away? <Yes> Is it normal to have the substrate give off a white cloudy mix every time I move it around? <Very normal to have cloudiness with crushed coral.> Should I simply try not to disturb the crushed coral? <Eventually it will settle down, get trapped in your filters, and removed with water changes.> Thanks so much for your advice! Mitchell Wexler <You are welcome. -Steven Pro>

Sand bed questions Good afternoon guys, hope all is well. <Very fine, thanks and I hope you are well too. Anthony> I have had to dose the tank heavily with calcium recently and have realized that I probably need to replace the sand bed after two and a half years. I have about two-three inches of aragonite and now understand that wasn't an optimal depth.  <yes...under three inches in my opinion is very challenging to maintain successfully. Almost impractical to have enough detritivores, water movement, etc. to compensate and prevent it from becoming a nutrient sink> I would like to replace it with live sand. One of my goals is to reduce nitrates.  <then a DSB with sugar-fine aragonite may be your ticket> I have a thirty seven gallon with a new CPR refugium and a Remora skimmer. So if I add about 1/2" in the main tank with 4"-5" in the refugium will that reduce nitrates noticeably? Currently they range from 10-40.  <I seriously doubt that the CPR sized refugium is big enough> I have a B. Cardinal, damsel and Pseudochromis in the tank now, but are only going to keep only the cardinal. I would like to change the tank over to mostly soft corals, with a pair of cardinals. <lovely... and if you are not afraid of them <wink>, do consider a long-spine blue dot urchin (reef safe-yes) if you get a bigger tank to grow up and let the cardinals live naturally among the spines> I currently have Kent bio-sediment in the refugium, would it be best to remove or could I mix with live sand to add extra mineral content?  <I might leave well enough alone (definitely not an endorsement of the Kent product though). I don't subscribe to mixing "magic mud" products and sand too much> I read several categories of the FAQ and it seems that you guys recommend changing half the tank at a time. Would it be a disaster if I did it all at once?  <rather challenging. I prefer to do it that way, but am hesitating to recommend it. I have more time than most people with real jobs to spend on my tanks <G>.> Or maybe the refugium then tank? It is going to be a huge project that I would like to do all at once. On another note I just purchased a R.O./DI unit and notice that I get a lot white sediment when I prepare the water.  <are you aerating it first to drive off the carbonic acid? if not... wasting a lot of buffer and creating insoluble bicarbonates(?)> I usually take about seven gallons add Kent Superbuffer dKH and let it sit a couple of days to come to temp., then add salt. Is this a good method?  <sounds like no aeration. With DI or RO water, it must always e aerated before ANY kind of use afterwards (fresh evap top off, or making seawater)> I guess that the sediment are minerals from the buffer? As always thanks for your help. Lowe <quite welcome. Kind regards, Anthony>

Substrate question <Anthony Calfo> ok - question, the recommended sand bed for denitrification is 3-4". Otherwise keep it shallow to prevent Hydrogen Sulfide release. This is usually using CaribSea Seaflor type of products. However, using the super fine (0.2-1.0m) grain Aragamax they claim that de-nitrification can occur using 1" floors.  <I couldn't disagree anymore with that statement> For safety sake, lets say 2". Is this a safe route to go about building a sandbed using Aragamax at 2" rather than 4 ? <Their argument is particularly ironic and funny that they only need 1" compared to 4" when all of the aragonite mined for our industry come the same single source (formerly Marcona Industries)...hehe. You just have to love a multi-million dollar industry without consumer watchdogs... I love this country!> I'm not quite willing to go 4" on an 18" tank, but 2" is reasonable ? otherwise, I'll stay shallow at 0.5" or so. <.5 and water changes it is> The other question is, with this fine sand, will it harden and make the lower areas hypoxic rather than anaerobic ? I've been told with non-reef based tank (basically no Kalkwasser), that this will probably not be a problem. <agreed...but, Kalkwasser is not the problem... Misapplied Kalkwasser is the problem with clumping> I imagine the sand sifting organism (hermits, crabs, gobies) will keep sift through it even though it packs down a bit. Any thoughts on using a shallower sand bed (2") with the much finer grain products ? <same as before and before.... 1/2 inch or less... 3+" or more... no in between> Thanks Ed <Anthony>

Substrate was Re: Ich question Anthony. The current CaribSea Puka is about 1/2" (barely covering bottom). <again... a labor intensive grade that is prone to trapping detritus...your call if you don't mind siphoning to keep it clean/sanitary> I've considered sand many times and could do it again. However from reading the FAQ's, is the DSB (about 3") good for a heavier bio-load FOWLR system ?  <yes in a properly managed system (adequate water flow, two skimmers, extra water changes, etc all appropriate for a heavy load tank> It contains eel, grouper, etc. As far as I know, eel and sand don't get along real well as they make a mess of it. . .  <some folks have complained about it... I have also had success with it including a 3' eel in a 500gallon display and several smaller species in smaller displays on fine deep sand. I am also very strict about not overstocking or overfeeding> I also opted not to since I didn't think I could keep any sifters alive in there (although you've mentioned one that could).  <there are many if you research/look into it to suit most any tank> Can a DSB keep up with heavier bio-loads or is it mostly more advantageous for reef based and light bioload systems ? <answered above> Water flow is heavy. 125 gallon is being pumped with 4 Maxi Jet's PH's (295gph), and return is Iwaki 70's (1500gph), so its about 10 times. Return is not broken up and fed from one side of the tank and forcing flow to the other end. That does bring up a good point, is it better to have powerheads down low pointing up or even to keep detritus up, or is better in the classic setup up high with the head pointing to whatever 'dead' areas you have in your tank ?  <any pattern that produces sufficient random turbulence to keep detritus in suspension is fine> If detritus suspension is the goal, wouldn't lower powerheads pushing current at the bottom be better ? <not necessarily if surface agitation is compromised to do so. Again...above recommendation for current> Again, can the DSB handle denitrification for higher bioload systems, or should a denitrator from Aquamedic (do these work) be considered. <no experience with the product> Obviously neither of the two will replace the small biweekly water changes. . . <exactly. Anthony> regards, Ed

Substrate was Re: Ich question III Hmm, yeah, I know the drawbacks with Puka shells. Been living with it for who knows how long. . . Guess it'll be time to switch one side of the tank and then the other. Here is a question though, is there any benefit to having a shallow sand bed (1/2" or so) ?  <simply aesthetic> The tank is only 18" tall, so I'm not sure I'm willing to allocate 4" to a DSB. . . <agreed> Yeah, my higher bio-load system, has a ton of filtration on it. I only have one skimmer, but its a dual-bucket system (two injectors) rated for 600 gallons. So I am over skimming a bit. . . < I certainly have no complaints with any skimmer that produces daily with consistency> Diverging to another question - can you have too many cleaner shrimp ? I have a few in the tank, but every once in awhile I lose one. So instead of constantly replacing one or two, can I drop like 6 or 8 of them in without any detrimental effect ? <sounds like a waste of precious life/resources until you figure out why they disappear or don't live for years. Anthony> Ed

Re: Substrate was Re: Ich question IV 1/2" of sand being aesthetic, but its more functional and better than 1/2" of Puka shells though, correct ? <agreed> I lose a shrimp to a lion every once in awhile. . . Not sure why the lion eats the shrimp that's cleaning it. . . One of those, biting the hand that feeds it in nature type of things. . . <wow... until these animals are captive raised, it seems like such a waste. I would not recommend adding any more. Anthony> Ed

Substrate replacement Hello again, it's me making a nuisance of myself. :D <No nuisance. What we are here for, to help.> I'm getting ready to replace my horribly old crushed coral substrate with Southdown sand. I got two 50 pound bags for my 55 gallon, I believe that should be enough. Am I correct? <Yes, 100 lbs. should give you about 4".> I cleaned one bag of sand last night (thank God my wife didn't wake up during that- she would have shot me if she saw the tub at the end of that...), and it's ready to go in. You had told me to do it one side at a time. I figured I'd do one side tonight and the next side next week... try to let some of the "bugs" (wife terminology mode) move over to the new stuff. <Good idea.> Just as I was all set to proceed, a huge question hit me like a brick. As I scoop up this old CC, it's going to get truly nasty in there. I probably should have coincided this with a water change, huh? <Yes, scooping will make a mess. See if you cannot find some vinyl tubing at the hardware store. 3/4" or 1" inside diameter and about 6' long and try to vacuum it out. Much less messy for the tank. All dirt and gravel goes into buckets.> Sometimes I wish there was no such thing as hindsight... I'd kick myself far less often. Guess I'll just start getting a change together tonight, and save this whole fun project for tomorrow... sigh... ~John <let us know how it turns out. -Steven Pro>

Replacing half of my substrate Bob, My 240 gallon FO tank has been running for a good year now. I want to vacuum out half of my crush coral substrate, and replenish it with new crush coral substrate. So that it will rejuvenate my PH . What do you think ? Good idea? or not? Thanks again, <A very good idea... more input on WWM (marine substrate FAQs) re actual steps to completion. Bob Fenner> Lee

Sand bed Hello Mr. Fenner, First, I'd like to thank you for all your previous help. You've been a Godsend for me. <A pleasure to serve> I have recently found a store that carries Southdown sand, and I'm going to buy some to replace my horrendously old crushed coral. My question is just a quick two parter: first- does this sound like a good idea? <Yes... good to switch out, augment such substrates about every year...> And, if so, how much should I get? It's a 55gal FOWLR setup, just two tangs (a yellow and a regal/blue/hippo/whathaveyou) and a lonely false Perc. <I'd suggest doing half at a time (left or right...) siphoning out (large diameter flexible tubing... and water can be pumped back in... maybe via a Diatom (tm) filter...) old and placing pre-rinsed new in its place (like thirty, forty pounds... but you can get more, use for other half later), wait a good month, siphon, replace other side> Thanks for any insights! ~John <And your intelligent writing. Bob Fenner>

Re: sand bed Shoot! Forgot to mention that it comes in 50 lb. bags. So, for my 55 gallon, do you think/feel I need 2 bags? <Yes... if you have some left over, it can be used for other purposes down the line. Be chatting. Bob Fenner> Thanks again! ~John

Mixing sand grains Hi Guys, <Harrow> Quick question please! I have a med sized sand (CaribSea Aragonite) <ech...> and bought additional sugar sized  <woo-hoo> Is it okay to place the sugar sized over the med-size?  <not recommended if your goal is denitrification (all fine for that). If not, please at least add screen between layers with course grain on the bottom> My plan is DSB about 6" deep.  <excellent!> Thank you guys you're doing a mighty fine job of educating us. <thank you for saying so, good sir. Anthony>

Substrate Anthony, thanks for quick response on last question. <my pleasure, good sir> Some questions about substrates.  I currently have Seaflor Aruba Puka in my 75 gallon fish only. <beautiful but not at all functional without serious water movement and activity on the substrate...speaking from experience> I was looking at switching to CaribSea special grade, but not sure if that is the best choice, would like some input. <equal size grain of whichever you choose... closer to sugar fine (oolitic) is better for denitrification. whereas coarse encourages more natural amphipods and the like> I'm planning on taking a third of the old out at a time. How long in between taking another portion of substrate out? <no hard and fast rule on this one... monitor nitrogenous elements to be sure. Intervals of weeks and not days for perspective> I was the one with the Koran and Naso and you recommended leaving my biomedia in my CPR wet/duty along with adding live rock. <yes... as a hardcore reefer (rock only) it took a lot for me to admit it...hehe. But the bio-load will be significant when these fish mature> Question is....I've seen that Seachem has a product which is a biomedia called matrix to replace the BioBale/bioballs. <I have no love for bio-bale...but I am quite content with bio-balls> It is suppose to complete the nitrogen process by turning nitrates to nitrogenous gas, is this stuff good/bad your input. <no experience with it, but dubious under a good bio-load such as yours> Reason I'm asking and no surprise to you, I've been getting an increase in nitrates, even with regular water changes (B/C of wet/dry). thanks Bryan. <indeed... the more efficient the bio-filter is as the fish grow, the worse the nitrates will get...almost ironic. You can look into various denitrification filters... some DIY (coil, Deep Sand Bed, batch, etc) but water changes will always be a best bet. Consider automating the water changes. Inquire if you go this route for assistance. Best of luck to you, Anthony>

Substrate Dear WetWebMedia crew, <You got Steven today working his shift.> I have a few questions about substrates.  After reading the FAQs and articles on substrate type and depth, I'm still a little confused.  I currently have a standard 55 gal. FOWLR plenum equipped tank with 3.5-4 inches of CaribSea Special Grade Reef Aragonite. <I have a 55 gallon reef tank with no plenum and 4" of the CaribSea Special Grade Reef Aragonite.  I hate it.  The grain size is too large and allows detritus to permeate into the sand bed.  The critters do not seem to enjoy it much either.  The Aragamax is a much better product from the same company.> There is also about 70+/- pounds of live rock in the tank.  Two power heads for circulation, CPR BakPak II, and CPR Hang-on Refugium.  Tank inhabitants include 4 neon gobies, 1 royal Gramma, 1 red spotted Hawkfish, and 1 spot fin butterfly (my pride and joy that I caught here in Maine 2.5 years ago), <I have heard of Caribbean fish straying too far north.  Grab me a couple of queen and French angels this summer.> 1 banded coral shrimp, a few snails, and a handful of blue leg and scarlet hermits.  I call it the Caribbean Critters Tank.  Anyway, in the near future I plan on upgrading to a 75 gallon tank and use the same rock, filters, skimmer, etc. In the new tank, I am not going to set up a plenum.  I would like to use just sand on the bottom (partly for aesthetic reasons) but was wondering about what grain size to use and how deep it should be for nitrate reduction?  I have read a lot of conflicting information about which grain size and depth to use.  Everything from Southdown Sand (from Home Depot) to the various CaribSea products.  I was also wondering if I could just use the current substrate right on the tank bottom and what depth would you recommend?  Another option would be to use either the Southdown or the other fine grain sands offered.  Any incite would be greatly appreciated. <I will soon be upgrading to a 120 reef and I already purchased 500 pounds of the Home Depot Southdown sand.  It is sitting in my garage with the tank, sump, and lights awaiting me building the stand.  I will use different sands for different tanks.  If it is a fish-only tank, I will use the Special Reef  Grade sand.  It is heavier and will not get blown away and cause a sandstorm, but I always keep it less than 1" deep.  For a reef tank, I now always use the fine grain sand (Aragamax, Southdown, etc.) at a depth of 4-6".  -Steven Pro> Hope Bob is enjoying his adventures (somewhere in the Middle East?). Sincerely, Jason B 

Substrate Follow-up Hi Steven, Thanks for the super fast reply.  Sometimes this technology stuff isn't so bad.  If I read your reply right, I'm okay with using my current substrate at a depth of less than 1 inch, as this future tank will be fish-only.  I also plan on adding a cherub (pygmy) angel and chain link moray to the collection.  Do you think the 1" substrate will be able to handle the nitrate load? <Sorry, I didn't specifically mention that.  No, a bed of sand that thin will do nothing for denitrification.  For that I suggest the use of purified water (RO, DI, Kold-Sterile), aggressive protein skimming (collection cup filled with skimmate the color of hot tea to coffee several times weekly), and regular partial water changes.> Or would I be better off going deeper with finer sand? <I believe a DSB can be overwhelmed by a heavy fish load in a lot of fish-only tanks.  Considering the light fish load you currently have and your intended additions, you may want to opt for the DSB.  The only other consideration is will your future moray create a sandy mess when he goes slithering around.  -Steven Pro> Thanks again. Jason B ps. Love this website and all the work you guys do. There isn't a whole lot of interest or information about marine/reef keeping up here in Maine.  Only one "real" fish/reef store and a few others that really don't try.

Substrates Follow-up Hi Anthony, Bryan again. <You reached Steven pulling his shift. I have been reading the daily FAQ's so I am somewhat familiar with the ongoing discussions.> Questions still about substrates. For my fish only 75 gallon tank would 1/2'' to 1'' be alright of CaribSea special grade, <Yes> I read where you said 3-5'' or 1/2'' or so is desirable. Now back to biomedia for my wet/dry. B/C of my (or going to have) high bioload (Koran and Naso) you suggested leaving the biomedia in filter but you don't care for BioBale. I'm going to make the switch to bioballs, what is the best way to make this change? take out 1/3 of BioBale and replace with the balls and do this till all replaced? <Sounds like a good idea.> Quick question on sumps. I'll have more detailed questions later. But I was wanting to take an old 20 gal tank and add substrate, live rock and algae, and put under my tank along with the wet/dry. Would this work? <Yes> And how to connect the two or be better to separate them with own flow from the main tank. I read the refugium needs a slower flow rate. <It would probably be better to keep these separate. A refugium does need a slower flow rate than what will be running through your sump. If you can do it, it is best to locate a refugium above the main display and to let the water gravity feed back to the main tank. Most people though cannot do this and hide their refugiums under the tank. -Steven Pro>

Reef Sand Hi Anthony or Steve, love the site. You guys are doing a great job in Bob's absence. <Thank you... but Bob is only absent in mind... not body...hehe. Anthony> Here is my question. I have a 2 year old reef tank that is up and running fine. I currently have crushed aragonite and was thinking of switching to sand to make the tank healthier. <agreed> Should I do this or leave well enough alone. <coarse media is more problematic long term. Fine sand has numerous attributes... not the least of which is denitrification of you fill at more than three inches deep> If I change, should I do a portion of the tank or all at once?  <rather laborious either way... with fewer/hardier livestock, I'm inclined to stress them once with a big but well planned complete change over... rather than repetitive insults> Currently I have about 45 - 60 lbs of live rock in my 55 gallon tank. <you might even add some more fresh live rock> Thanks for your help. Ray <quite welcome. Anthony>

Nitrates and Substrates Hi bob- <Anthony Calfo in your service while Mr. Fenner has hit the road with the traveling Bob Show> Your web-site has given me info overload....in a good way. <now try browsing the site with only actinic lights on in the room and Pink Floyd music playing in the background> For starters, I have a 55 gal salt tank. Assorted tangs, choc. chip star, green brittle, 2 peppermint shrimp,2 small urchins and a feather duster. Tank is about 5 years old. <just curiously...how many tangs and what kind in the 55gall?> The substrate is a crushed coral, average size is about that of a bb. I have a big double wheel emperor filter on the back, a Prizm protein skimmer, a magnum 350 canister that is full of bio-balls and covered with a floss filter and 1 powerhead. Lighting is 2 55w compact flour. daylights and 2 55w blues. The stronger lighting and protein skimmer are new additions in past few weeks. <excellent...you'll appreciate them ever more in time> I did a 15 gal water change with the nitrates between 25-50mg/l. I use a vacuum siphon and dig down into the coral .  <the phrase "dig down" into the gravel is a bit scary... if you aren't already doing it, gravel siphon the top inch of a three to five inch substrate and no more than that. Particulates shouldn't make it much deeper if you are not overfeeding or have enough detritivores, and you stand to do more harm than good by compromising the fauna> On recommendation from my LFS I rinsed out half of the bio-balls in tap water because they were very packed with muck.  <I'm glad you rinsed them (although I would have used aged water from the tank from a water change before discarding it). However...for future reference... they should not accumulate any such muck. Either the pre-filter isn't working properly, there is a design flaw or perhaps you got busy or forgetful on prefilter maintenance> I was not sure water was getting through them. Anyway, The day after the water change the nitrates were off the scale ,100+, and the fish were puffing quite rapidly. I changed another 5 gal the next day and it may have brought nitrates down a bit. But the poor fish look like they are suffocating. I use tap water that is conditioned with a chlorine/chloramine neutralizer. It checked ok when tested for nitrates. I have had this tank for years with no major problems and my routine has not really changed.  <if the gravel siphon was aggressive, you may have liberated noxious elements. The fact that your bio-balls accumulated any matter at all on them suggests that you a problem with nutrient export processes (which are on the mend in part with the skimmer<smile>> The bio-ball rinse after 4 years was a first though. <not the immediate problem... couldn't produce nitrate that fast (takes days to weeks)... it was a necessary evil> And the recent addition of skimmer and new stronger lights. When I was siphoning the bottom this time I moved some of the larger rocks and some large amounts of dark green or brown matter came out. I have a feeling that it was good stuff. <not sure I follow you thinking...sounds like accumulated detritus/sediment (bad stuff most often)> My thinking (after long conversations and lots of time on your web site) is that the increased flow in the bio-balls is producing more nitrates and that I destroyed some (or a lot) of the good bacteria in the substrate that convert nitrates.  <I disagree on the first count if the time frame is hours to a couple of days, but I agree on the second count> But the LFS tells me that nitrates are not that harmful <Wow...a very broad statement ... more false than true. Small amounts of nitrate harmless or necessary for marine life, large amounts fatal... beginning with tangs, angels and butterflies> and something else must be causing the increased respiration. I feel that I am a bit out of my league on this one. HELP!!!! <it simply sounds to me like the misapplication of course substrate which easily traps detritus (as you have noticed) has finally caught up with you... you are making good changes to help the water quality> They also suggested that I push the coarse crushed coral towards the back and put a layer of finer coral on top of that and then top it off with a thin layer of sand. And then never vacuum the bottom again. Is that a good idea? <quite frankly the idea horrifies me. I am glad you are seeking second opinions. Crushed coral by virtue of its size is inherently going to trap detritus. The rule of thumb for many aquarists with a static bed of substrate (no flow trough) is 1/2 inch or less OR five inches or more. And with a deep substrate you'll need finer sand and/or adequate detritivores to keep it serviced properly. The advice of your LFS will only trap nutrients in this case> What are your thoughts? This is a new problem for me and I want to make sure I can correct it as soon as possible. <if it isn't now or going to be a hardcore reef tank, you do not need or want a deep substrate. You might consider siphoning most of the gravel out and only leaving a 1/2 inch behind. Any more will trap sediment too easily, but shallow media can be cleansed with good water movement which keeps sediments in suspension for nutrient export (skimmer, etc.) The poor fish are really working the gills I hope I provided enough pertinent info. I am sorry this is so long winded but I thought it would make it easier for you to help me. Thank you in advance Dennis <keep reading and asking questions, bud. Best of luck, Anthony>

Oolitic Sand and Milky Water Hello Bob, I have one more quick question... <You got Steven because Bob is off traveling the great Midwest.> First off, thank you for the helpful information you gave me yesterday!! My question is: I Have just started a saltwater tank (This is day 3). I used very fine grain sand/coral for the bed of my tank and instant ocean salt. My problem is that my tank looks like milk, and it's been 3 days!! <This is not unusual with fine aragonite sand. It will usually disappear on its own. You can help by adding a mechanical filter or doing the water change. Just be sure not to disturb any more sand.>

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.

Is Pink Fiji Sand O.k. stuff? Bob, Thanks for the help lately. Much appreciated. <You're welcome> Is there any reason not to use Pink Fiji Sand in my main tank? I plan to have stars and maybe a sand sifting blenny. I forgot who it's packaged by, the packager is something like Custom Imports (they package aragonite sand also). Anyways, it's made for marine tanks, but wanted to make sure there wasn't any reason not to use it.  <None I'm aware of> I already have a sump with a plenum using aragonite sand to help with buffering, but wanted something a little more fine and appealing in the main tank. I assume you have to keep an eye out not to get this stuff too deep, in case of it going anaerobic. Do you recommend a max or min depth? <Not really... but to do as you suggest... keep it stirred, an eye on it...> Thanks again. Got your book (CMA) last week, love it... <Ah, good to hear/read. Be chatting. Bob Fenner> Dan

Moving Substrate to sump, and what kind of Carib-Sea to get? Bob, Thanks for your help recently. <You're welcome> I'm adding a 20 gallon or so sump to my 38 gallon FOWLR. It will have a plenum and macro-algae. I currently have Carib-sea Geomarine crushed coral in my main tank, about 1" deep. I want to change to sand in the main tank. <Good idea> Three things: I want to use the crushed coral from the main tank as the bottom layer in the new plenum for the sump. Is this the right size crushed coral for the bottom layer, and is it o.k. to use the current crushed coral? Or is there a better bottom layer material. <Should be okay... use a plastic screen mesh (like material available for screen door replacement) on top of this layer and finer material (likely coral sand) on top...> I want to change to sand in the display tank. I'm hoping you are familiar with the different Carib-sea kinds of sand. <Yes> What is the best choice for the main tank. It won't be a deep sand bed. The choices are Carib-sea pure Caribbean Aragonite(0.18-1.2mm), Carib-sea Aragamax(0.5-1.02mm), or Carib-sea Special Grade(1-1.7mm) I would like to have a blenny or starfish in the main tank. <Myself... would go with the last (Special Grade)> Of the three Carib-Sea choices above, what is the best choice for the top layer of the plenum? <As stated> Thanks a million, you're an excellent resource, and your book should be arriving on my doorstep today courtesy of UPS. Dan <Be chatting, and taking up your time... pleasurably, my friend. Bob Fenner>

Help! (big "old" tank, tear-down candidate) I need advice: I have a 220 gallon reef tank with a sand bed that was originally about 5 inches deep. It is now about 3 inches deep. It has been set up about four years. All parameters are fine, except the alkalinity is down somewhat. <Yes... the more easily soluble parts of your substrate have melted... the other two inches... and now there is no ready source of alkaline, biomineral reserve> I now have an algae cesspool....hairy as well as bubble. No matter what I try, it does not get any better. <Mmm, no worries... easy to not ways to fix> I have been told by others that when the sand bed gets this small, it is a nutrient cesspool and needs to be ripped down. (BIG project! - ugh!) I was told it is a nutrient sink and needs started all over. <Not so much a sink... as not a reservoir of carbonates, bicarbonates, calcium...> Are their alternatives? Adding more sand at a time? Stirring it? Additives? I really do not want to rip it apart....it is built into a wall and a real project to do. Thanks! <You can/could do a few things here... I would probably take this system apart at this point (easiest, best, long-term fix)... replace the substrate, add more/replace the live rock, substrate. Please read over the set-up, live rock, marine substrate sections on WetWebMedia.com re specifics. Bob Fenner> Ron Cypher, MD

Re: help! Thanks for the fast (but depressing!) reply. <Ahh, you're welcome... as stated... what I would do... there are some "stop gap" measures you could take... siphoning out part of the substrate (half, side to side...) and replacing it, adding live rock over what you have... I would go the overall tear-down, re-set-up route> Does this mean every four years or so I must rip it apart and start all over? <No... better to at about a year and a half or so start an every year process of renewing/replacing part of the substrate and LR... as detailed on WWM> Are you sure I can't just add more sand??!! :) :) ??? <You could... but wouldn't really "do the job"...> Thanks! Ron PS I loved your speeches in Pittsburgh! <Hopefully as much as I enjoyed presenting them. Be chatting. Bob Fenner>

Re: help! One last question: (for now!) <Mmm> would I be better off with just the live rock and a small amount of sand and skipping the deep sand bed? I never realized it required that much maintenance (I have four reef tanks with deep sand beds). <I do use substrates... most systems are far better off with them than not. Bob Fenner> Ron

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