Sand depth...

[NanoReefer1]

I have been looking around at some other 10 gallon nano reefs, and I have seen some sand beds that are like 2-2.5inch deep when my sand beed is at best maybe 1-1.5inch at most. Will my 1-1.5inch still provide me with enough biological filtering?

Also another question I have is wether or not I can add to the amount of sand I have in the future, and if I can smooth the top of the sand out in order to get a even landscape.

Thanks.

[Reefland]

Hey Nano,

It is said that the minimum depth of a sand bed to provide any denitrification capacity is 3", so unless you a prepared to go this deep (or deeper) there is no reason to add more.

[NanoReefer1]

Would it be more beneficial for me to run a DSB?, and if I wanted to how would I go about introducing the new sand without stress(spikes) to the tank setup just 16days ago?

Also will moving the live rock cause any spikes? or Just leveling out the sand in the tank after moving the rock?

thanks!

[Ninong]

It is said that the minimum depth of a sand bed to provide any denitrification capacity is 3"

Scott,

It is not factually correct to say that 3" is the minimum depth to achieve "any denitrification capacity." No one that I know of has ever made that claim.

Over the past decade or so, the guys who favor deep sand beds have suggested various minimum depths as the minimum depth they believe will provide all or most of the benefits to be had from a DSB. They were never talking about just denitrification. Even the ones who actually believed that a minimum depth of 3" might be required for optimal denitrification still accepted the proposition that at least some denitrification can be had at depths as shallow as 1.5-2", especially if the sediments were very fine particle sizes.

To summarize the writings of Dr. Ron Shimek, who is probably the best known of the DSB advocates, his minimum depth recommendation has always been 4" (10 cm), although he has on occasion agreed that 3.5" (9 cm) would work. Ron's recommendation is NOT based on just denitrification capacity. He is a strong advocate for a very lively DSB that incorporates a diverse array of infaunal life that participates in the various biological and chemical reactions that take place in a DSB. And it is this infaunal life that keeps the sand grains in motion preventing clumping.

Dr. Ron has also stated on several occasions that it is impossible to maintain a viable DSB of the sort he recommends in a nano tank of say 20 gallons or less. On several occasions hobbyists have asked him if it is worthwhile setting up a 4" DSB in their 20-gal aquarium and he has told them not to bother because it can't be done. What he's talking about here is the minimum mass (volume of sand) necessary for the establishment of a viable, sustainable population of diverse sand bed infauna. If the volume of sand is too small, these populations will crash. He's not talking about just denitrification.

Over the years the minimum sand bed depth recommended by the various hobby authors has varied from ~2" (Delbeek & Sprung) to 8" (Lowrie). Rob Toonen recommended a minimum of just over 3" and Ron Shimek recommended a minimum of 4". Delbeek & Sprung have both moved towards slightly deeper sand beds over the past decade. The Germans, on the other hand, when they weren't recommending no substrate at all (pure Berlin method), recommended a substrate of coarse crushed coral ~1 cm deep. That was several years ago, many of the Germans now employ DSBs.

Conventional wisdom has always been that fine grain sediments would provide more denitrification benefits than coarser grain sediments in sand beds of similar depths. The thinking being that the finer particles provided more surface area for colonization by denitrifying bacteria. And conventional wisdom has always held that a deeper sand bed would provide more denitrification benefits than a shallow one. For one thing, you need areas of little or no oxygen for denitrification to take place. I don't disagree with these suppositions; however, the experiments supervised by Dr. Rob Toonen a few years ago sort of knocked conventional wisdom on its ear to a certain degree.

Rob set up 24 small nano tanks: 3 with crushed coral 3.5" deep, 3 with fine particle (Southdown sand) 3.5" deep, 3 with crushed coral 1" deep and 3 with fine particle (Southdown sand) 1" deep. That's a total of 12 tanks. He also set up another 12 tanks just like those but with a plenum. That gave him a total of 24 tanks. I won't discuss the plenum tanks except to say that Rob found no differences between the plenum tanks and the tanks without a plenum.

The surprise was that Rob found that:

In terms of processing nitrogenous wastes from aquarium inhabitants (specifically ammonia, nitrite and nitrate), none of the experimental treatments (plenum vs. sandbed; deep vs shallow; coarse vs. fine) appeared to have a significant advantage (Figs. 7-9).

That was more than a surprise, it was a shock. However, it is what it is.

None of the systems appeared to reach their maximum processing capacity for nitrogenous wastes, because within two weeks of the start of each experiment, no ammonia or nitrite was detectable in the aquarium water through the end of the experiment (Figs. 4-5). Likewise, the rate of increase of nitrate in the experimental tanks was far less than the rate of addition to the aquaria (Fig. 6). Thus, each sediment filtration design tested herein appeared capable of handling the test bioload, and there did not appear to be any significant benefits for aerobic nitrogenous waste processing derived from any of these various experimental designs.

Denitrification must have occurred in all experimental treatments, because nitrate concentrations did not continue to climb throughout either the dosing (Fig. 6) or live animal (discussed in detail in Part 2 of this series) experiments. Despite continued addition of NH4+ at a rate of 0.5mg / L / day in this experiment, which was metabolized quickly enough to keep ammonia and nitrite at undetectable levels (Figs. 4-5), nitrate concentration in each tank was maintained at a fairly constant level throughout the latter 60 days of the experiment (Fig. 6). However, similar to the results seen with ammonia and nitrite processing, there was no significant differences in the ability of any of the experimental treatments (plenum vs. DSB, deep vs. shallow, or coarse vs. fine sediments) to reduce nitrate in these closed systems.

Each of the designs tested was capable of handling denitrification of the ammonia added to the tank, which equalled the bioload of a heavily stocked tank of that size. None of the designs tested maxed out. That means that the 1" crushed coral sand bed handled denitrification of the test bioload and the 3.5" fine particle sand bed handled denitrification of the test bioload, as did the 1" fine particle sand bed and the 3.5" crushed coral sand bed. They all handled the denitrification of the test bioload without problems. There were no significant differences in performance. To say that that was a surprise is an understatement.

The significant differences among the experimental treatments were almost entirely in the buffering capacity of the sediments rather than the biological breakdown of nitrogenous waste products. The largest differences among the treatments were seen in the final concentration of phosphate: coarse sediment treatments had roughly 17 times the final concentration of aquaria in fine particle treatments!

Rob found significant differences in the buffering capacity between fine particle sediments and coarse particle sediments. Remember again that he used Southdown aragonite sand for the fine particle tanks and Florida crushed coral for the coarse particle tanks.

Rob's article can be found here.

P.S. -- I think it's important to remember that Rob's experiment lasted only about 4 months and that the tanks were very small. It's quite possible, at least in my mind, that a tank with a 3.5" crushed coral sand bed could develop problems relating to trapped detritus over a longer period of time and with actual fish, etc., in the tank.

Rob found that fine particle sand beds were better at buffering than crushed coral sand beds but that all of the test sand beds were capable of denitrification. I would still not want to try a crushed coral sand bed but maybe that's just me.

[Ninong]

I have been looking around at some other 10 gallon nano reefs, and I have seen some sand beds that are like 2-2.5inch deep when my sand beed is at best maybe 1-1.5inch at most. Will my 1-1.5inch still provide me with enough biological filtering?

Your 1.5" sand bed will provide biological filtering as will your live rock. A 2-2.5" sand bed would provide more biological filtering but you may have adequate filtering with what you have now.

Also another question I have is wether or not I can add to the amount of sand I have in the future, and if I can smooth the top of the sand out in order to get a even landscape.

Yes, you can smooth out the surface of the sand bed if that's the way you like it. Some people prefer a sand bed that is not even.

If I were you, I think I would leave the sand bed alone. Your tank is a 10-gal nano tank and I think you have adequate filtration already between your live rock and your sand bed. If you read my above post, you will see that the only significant difference Dr. Rob Toonen found between sand beds of shallow (1") and deep (3.5") design composed of either fine particle aragonite or crushed coral aragonite was the the fine particle sediments provided more buffering capacity than the crushed coral sediments. In your case, your sand bed will provide zero buffering capacity because it is not aragonite, it's fine particles of volcanic lava. The very hot lava (2000 degrees Fahrenheit) explodes when it comes into contact with the cool waters of the ocean. This is how black sand beaches around the world are created.

[NanoReefer1]

I think they mixed crushed aragonite in with the black sand, and that is how they got away with calling it Bio-Activ Live® Aragonite Black Beach.

So if it had crushed aragonite as a component in it then it would buffer right?

Also on the Nature's Ocean website it lists as one of its properties "Reduces algae growth " therefore this could be through nutrient buffering could it not?

and when I look closely at the sand I see alot of white fragments, and white sand mixed into the black because it is not 100% black.

[Ninong]

I think they mixed crushed aragonite in with the black sand, and that is how they got away with calling it Bio-Activ Live® Aragonite Black Beach.

No, I don't think so. As you previously pointed out, their ad copy says "Collected in its natural environment and packaged in its natural state," and as you correctly observed previously, it appears to be identical to Carib-Sea's Tahitian Moon substrate, except that Carib-Sea doesn't make the absurd claim that Tahitian Moon is "black aragonite" like Nature's Ocean does.

Look at this photo of Nature's Ocean



and compare it with this photo of Carib-Sea's Tahitian Moon.



Carib-Sea even makes a point of telling you that Tahitian Moon will NOT affect pH. That's because it's not aragonite. Both products probably come from the same source. What has happened here is that someone at Nature's Ocean, either in the company itself or in their advertising agency, did not realize that their black sand was not aragonite like their other products. It appears to be just a dumb ad copy claim that somehow or other slipped in there.

So if it had crushed aragonite as a component in it then it would buffer right?

Aragonite has a certain amount of buffering capability. There is a wide difference of opinion on whether this buffering capability is overrated or not.

Also on the Nature's Ocean website it lists as one of its properties "Reduces algae growth " therefore this could be through nutrient buffering could it not?

The first thing you have to remember is that not all of the claims made in a seller's advertising copy are true. In fact, with some products, none of the claims are true. The most hilarious examples of this can be found in the claims made for some of the magic potions that are offered for reef aquariums.

You're misunderstanding the term "buffering." It has nothing to do with nutrients at all. Buffering refers to the ability to maintain pH at a certain level. It's also used to refer to calcium and alkalinity maintenance in aquariums. In other words, whenever you see a claim that a certain product will assist in buffering, they're talking about the maintenance of proper calcium, alkalinity and pH values. This has nothing to do with nutrients -- nitrogen, phosphate, etc.

...and when I look closely at the sand I see alot of white fragments, and white sand mixed into the black because it is not 100% black.

It may not be 100% black but it appears to be mostly black (like better than 95% black) and they claim that it is "collected in its natural environment and packaged in its natural state," so we can assume that it is mostly volcanic sands from black beaches, which is what they claim. Except that Nature's Ocean incorrectly refers to it as "black aragonite." That's because they don't know any better.

[NanoReefer1]

Are there any negative to this? As in ones that would necessitate me starting over?

[Ninong]

Are there any negative to this? As in ones that would necessitate me starting over?

There are no negatives that I am aware of. I wouldn't personally choose this sediment for a reef tank but it's quite natural, just visit Hawaii sometime. They have white beaches and black beaches.

This question has been asked before on another board and Dr. Ron Shimek responded that the black sediments would not release anything harmful into the aquarium.

[NanoReefer1]

Will I get worse end results with my aquatic life with black sand v.s. white aragonite?

[Ninong]

Aragonite sand is calcium carbonate. It's composed of the skeletons of hard corals that have been pulverized into sand over time. Parrot fish, for example, eat hard corals for the zooxanthellae they contain, expelling the ground up coral skeletons as they go along. Aragonite sediments are also created by precipitation (the Bahamas, for exmple). The remains of calcareous algae (such as Halimeda) makes up a considerable portion of some calcareous sand beaches. The shells of foraminiferans are added to calcareous sand beaches, which happens to explain the pink sand beaches of Bermuda (remains of Homotrema rubrum mixed in with the sand).

The skeletons of hard corals are aragonite. Therefore, when aragonite dissolves it releases calcium, magnesium, strontium, etc., in the exact same proportions as required by growing corals. The question of whether it dissolves in a reef tank is a matter of some debate. Or, I should say that the extent to which it dissolves is a matter of debate. Aragonite doesn't even begin to dissolve until the pH gets down around 7.7. It's not going to get that low in the water column but it might get that low deep in the sand bed. Aragonite media is used in calcium reactors but carbon dioxide is injected to bring the pH down into the mid-6's so that the aragonite will dissolve readily.

In any case, aragonite is credited with the ability to assist in buffering (maintaining proper pH). Aragonite, in my opinion, is the most natural choice for sediment in a marine aquarium. There are some who hold that it really makes no difference at all whether your sediment is aragonite or regular quartz sand or volcanic sand or whatever, provided the particle sizes are the correct sizes (meaning small). They are probably correct but I still prefer aragonite.

[NanoReefer1]

Nature's Ocean - Premium Marine Subtrates
Black Beach Sand #1
Premium Aragonite Reef Sand:
Ideal for reef system tank bottoms, denitrifying anaerobic beds, extremely high surface area filter media.
Aragonite Benefits:
Reduces Nitrates. Maintain pH. Increases Carbonate Hardness. Provide Marine Trace Elements. Pre-washed Minimum Rinse Required. 100% From The Ocean Floor. Heat Sterilized. Ideal for culturing Live sand.
Item #: 10261
UPC: 029904102610
Grain size: 1.2-1.7mm
Packaged: 2 - 20 lb Bags per case
Net Weight: 40 lbs


Just found this... more information on my sand very interesting. I guess I could always give it the vinegar test to see if it was or not.

Lol but if it isnt I think im going to give the company a call and tell them to knock it off on the false advertisement before I turn them in to the Better Business Bureau

[Ninong]

Take about a teaspoon of black sand and add it to about a quarter cup of vinegar. Any aragonite will dissolve. Any quartz or volcanic sands will not dissolve.

Or just drizzle a few drops of vinegar onto dry sediments and see if it fizzes or not. Aragonite (CaCO3) will react with acid (vinegar) to release carbon dioxide. If you use enough acid, you can dissolve it completely. Ordinary white vinegar is 97% water and 3% acetic acid. You can also use muriatic acid ( hydrochloric acid). It's much stronger than vinegar.

P.S. -- "Reduces Nitrates" -- that part of the ad copy is correct. In fact, that would be correct for any sediments but it's not the sediments that are responsible, it's the denitrifying bacteria that will colonize the sediments. The other claims would only apply to aragonite and certainly the black grains are not aragonite.

P.P.S. -- The particle size (1.2-1.7mm) is rather large.

[NanoReefer1]

Ok will do... thanks like it matters though lol I already got it in the tank! LOL Ohh well time to call there bluff.

[Ninong]

Ok will do... thanks like it matters though lol I already got it in the tank! LOL Ohh well time to call there bluff.

Tell them that you put some of their "black aragonite" sand into a small cup of vinegar and it didn't dissolve. It didn't release any carbon dioxide either. Ask them to please explain to you why their aragonite doesn't react with acid.

Also, you might forward them this photo of aragonite and ask them why it's so white looking. Tell them you looked all over the Internet but you couldn't find any photos of "black aragonite," except for the ones on their website.



Then you can tell them that all the guys over at Reefland.com are laughing at the claims made in their ads for "black aragonite reef sand." One of the moderators even said they're a bunch of idiots.

[Future]

I myself have been looking into different substrates for my 75gal. build and I'm pulling no punches with it either, so this may help you a bit about Aragonite. I had assumed it would be a black color because it's on a metal side of the scale, but I was surprised myself. Personally I've decided on a mixture of 1/3 CC and 2/3 sand.
Everyone hears about the 3" DSB, but from what I've read being it is a biological filtration method, the deeper the better, but 3" was always a "Rule of Thumb" thing.

• Color can be white or colorless or with usually subdued shades of red, yellow, orange, brown, green and even blue.
• Luster is vitreous to dull.
• Transparency: Crystals are transparent to translucent.
• Crystal System is orthorhombic; 2/m 2/m 2/m
• Crystal Habits include twinned hexagonal prismatic crystals as well as a diverse assortment of thin elongated prismatic, curved bladed, steep pyramidal (spiked) and chisel shaped crystals. A branching tree, coral or worm-like delicate form is called "flos ferri". Can also be compact, granular, radially fibrous and massive. Its massive forms can be layered, coralloid, pisolitic, oolitic, globular, stalachtitic and encrusting. Aragonite is a constituent of many species' shell structures. A layered sedimentary marble like formation is called Mexican Onyx and is used for carvings and ornamental purposes. Calcite pseudomorphs of aragonite crystals and formations are common.
• Cleavage is distinct in one direction (pinacoidal).
• Fracture is subconchoidal.
• Hardness is 3.5-4
• Specific Gravity is 2.9+ (average for non-metallic minerals)
• Streak is white.
• Other Characteristics: aragonite effervesces easily in cold dilute hydrochloric acid, is strongly birefringent, is fluorescent and its refractive index is 1.7 .
• Associated Minerals include gypsum, barite, smithsonite, malachite, calcite, serpentine, sulfur, celestite, zeolites, quartz, clays, dolomite, limonite, chalcopyrite and wulfenite among many others.
• Notable Occurrences include Aragon, Spain (its type locality and from where it gets its name); Morocco; Bastennes, France; Girgenti, Sicily; Alston Moor and Cleator Moor, Cumberland, England; Baja California, Mexico (Mexican Onyx); Tsumeb, Namibia; Carinthia, Austria; Leadhills, Scotland; Harz Mountains, Germany and in several localities in the Southwestern United States.
• Best Field Indicators are crystal habits, single plane of cleavage and reaction to acid.

[Ninong]

Personally I've decided on a mixture of 1/3 CC and 2/3 sand.

In my opinion, that is a terrible choice. Over time, all of the crushed coral will rise to the top.

Color can be white or colorless or with usually subdued shades of red, yellow, orange, brown, green and even blue.

That has nothing to do with aragonite sand. ALL aragonite sand is white and comes from the same place in the Bahamas, where it is mined by Marcona Ocean Industries. It was all formed over millions of years by precipitation -- the Bahama Banks.

P.S. -- For more information on aragonite sand, see my posts #5 and #7 in this thread from 2001. One thing that has changed since then is that CEMEX sold their Southdown aragonite sand division to Oldcastle.

[Future]

In my opinion, that is a terrible choice. Over time, all of the crushed coral will rise to the top.

Interesting! I hadn't thought of that. I figured it would be like a typical sandbox setup where the larger objects tend to sink.

That has nothing to do with aragonite sand. ALL aragonite sand is white and comes from the same place in the Bahamas, where it is mined by Marcona Ocean Industries. It was all formed over millions of years by precipitation -- the Bahama Banks.

P.S. -- For more information on aragonite sand, see my posts #5 and #7 in this thread from 2001. One thing that has changed since then is that CEMEX sold their Southdown aragonite sand division to Oldcastle.

I heard that there was a company who would harvest the aragonite and crush it into a particle form then disbursing it out into the ocean. I forget the name of the company, but this was something from long ago that my grandfather said he aided in building the plant (Union Construction)
Maybe they did something else with it

[Ninong]

I heard that there was a company who would harvest the aragonite and crush it into a particle form then disbursing it out into the ocean. I forget the name of the company, but this was something from long ago that my grandfather said he aided in building the plant (Union Construction)
Maybe they did something else with it

"In the Bahamas, the mineral aragonite or 'white gold' occurs in shallow waters lying off the islands of Andros, Bimini, and Eleuthera. The material forms as an oolitic precipitate during the interaction of calcium-saturated cold waters with the Gulf Stream and the warm, ubiquitous shallows surrounding the islands. Spring tides carry the seawater into shoals where the water mixes and rises in temperature, causing its calcium carbonate to precipitate around nucleic material into concentric laminates. The process contributes to a high and consistent calcium carbonate value (95 to 98 percent) within the oolites. Investigators estimate the collective tonnage of aragonite in the region at some 100,000 million."

"Marcona Ocean Industries Ltd, the Bahamas' only aragonite concessionaire, uses a suction dredge to extract the aragonite from the seabed at depths of 1m to 8m. Dredged material is transferred in slurry form to a barge where it is screened and sent by 1,500-tonne self-uploading barges to an onshore stockpile on a 96-ha combination of natural cays and interfilled area, collectively referred to as Ocean Cay. Here the final, stored product awaits shipment to U.S. and Caribbean markets."

Reference: Marine Mineral Resources; Earney, Fillmore C. F., 1990.

As far as I know, Marcona Ocean Industries is still the only aragonite concessionaire in the Bahamas. As far as I know, the Bahamas is the only source of aragonite sand in the world. If anyone knows anything different, I would be glad to hear it.

[Future]

Ya got me, My grandfather is old. What was actually done shall remain a mystery to me, nor does it really matter how things were done back during the war. However what I recall him saying was they barged in enormous boulders of the stuff and sent it through some kind of plant that utilized it.