Lets Talk Substrates for the Marine Aquarium

[Maritimer]

The "live" sand generally doesn't recommend rinsing - but it can still be mighty cloudy for a few days. There are plenty of folks who feel that the touted benefits of live sand are negated by the siltiness of it. I used live sand without rinsing to start my tanks, and also committed what might be considered the "cardinal sin of sand" by transferring 80 pounds or so from an existing tank. (That sand, however, was rinsed thoroughly!) Rinsing can be done in a bucket, with a hose, a few pounds at a time, until the water runs clear. It's a chore, for sure!

~Bruce

 

[kirstyflash]

We have a Cade400 set up bb atm with a few rocks, a terracotta pot for a pair of clowns, 2xgbta, bicolour Blenny, coral banded shrimp, alveo, purple stars, a few baby trochus and turbos. I don’t like the look of the bb. I have seen a tank with black quartz gravel and am thinking of putting down a shallow bed of this. Anyone had black gravel quartz? Pros and cons?

 

[Arcticfirefighter]

I just used 20lbs of live sand in my new 36 Bow and it covered the entire bottom in about an inch of sand. I got worried after adding the water because the tank looked like milk. However, it started to clear a bit after the actual sand settled overnight. The sand "dust" was another matter and took about 3 days to clear. I also ran a cheap HOB during the process to clear out the dust. After that three days the water was crystal clear. One thing to remember is to check your filter often. I was washing the "dust" off the filter about every 12 hrs.

 

[SamiBlue]

Hey does anyone know if activated carbon would make a suitable substrate? It always comes with my filter floss and I'm not sure what to do with all of it. =p
Plus I thought the black would look more interesting.

 

[beaslbob]

Hey does anyone know if activated carbon would make a suitable substrate? It always comes with my filter floss and I'm not sure what to do with all of it. =p
Plus I thought the black would look more interesting.

not in my book. Just too expensive.
the activated carbon aspect would be used up very quickly. So just a plain black porous gravel would be much cheaper and probably do the same thing.

my .02

 

[lapin]

Hey does anyone know if activated carbon would make a suitable substrate? It always comes with my filter floss and I'm not sure what to do with all of it. =p
Plus I thought the black would look more interesting.

Depends on what you want to grow.
"A downside to activated carbon is that it will increase phosphate levels in the tank, which in turn is implicated in the boosting of many kinds of algae in everyday aquaria.
Really cheap, low quality carbon, heaving with ash, will even boost pH in your tank, sometimes dangerously so. As luck would have it, you’ll usually find that these cheaper brands will also be the worst for leaching phosphate, so with carbon it’s often a case of getting what you pay for. If it looks too cheap to be true, it probably is."

 

[Reef-junky]

Depends on what you want to grow.
"A downside to activated carbon is that it will increase phosphate levels in the tank, which in turn is implicated in the boosting of many kinds of algae in everyday aquaria.
Really cheap, low quality carbon, heaving with ash, will even boost pH in your tank, sometimes dangerously so. As luck would have it, you’ll usually find that these cheaper brands will also be the worst for leaching phosphate, so with carbon it’s often a case of getting what you pay for. If it looks too cheap to be true, it probably is."

Good information to know.

Thanks for posting

 

[JakeW]

Thanks for posting. Great topic that causes a lot of issues if done wrong.

 

[jjflounder1]

Carbon is also VERY LIGHT and blow all over heck ...with any decent flow ...

 

[Tom Giddens]

I was reading about the animals eating all of the bacteria and microfauna. I was planning on adding those things back to the tank every few months by using a refugium and some of the live bottled products offered today. Will this work?

Lets Talk Substrates for the Marine Aquarium

Bare-bottom (BB)? Calcium Carbonate (CC) Gravel? Crushed Shell? Sand? Deep vs. Shallow? With all the choices that are out there, no wonder new hobbyists are often confused about which substrate to use for their marine aquarium. In this thread, I shall attempt to address pros and cons of each of the available substrates.

Please remember however, that the choice of substrate must be balanced with two things; Aesthetic value to the viewer and biological value to the livestock. Some fish and inverts require a certain type or depth of substrate, and proper research should be done to ensure that the hobbyist is correctly matching the substrate with the needs of the aquarium's livestock. Sand-sifting gobies such as the Diamond Watchmen and Yellow Shrimp gobies should never be placed in a BB or CC gravel tank, and many wrasse species require a Deep sand bed (DSB) so that they may bury themselves at night or when they perceive themselves to be in danger.

Bare-Bottom (BB): Bare-bottom refers to an aquarium that has no substrate at all. The bottom remains clear, and allows the hobbyist to easily clean up any left over food or debris which may be floating around, using a net, siphon, or state of the art filtering system. This lack of substrate is preferred by those hobbyists who prefer a clean, sterile look in their aquarium, and is often recommended for a quarantine tank. While maintenance is easy, it must be done regularly as debris blowing around the tank can be very unattractive. The lack of substrate means that the hobbyist is gaining no natural filtering benefit from the substrate and is unable to keep sand-dwelling inverts or sand-sifting fish. Additionally, Extra care must be taken when building rock structures or when working in a BB tank as there is nothing to absorb the impact should a rock wall collapse. And finally, refugium lights on a reverse cycle can shine up through the glass bottom, causing the aquarium to be lit from below; therefore individuals may wish to consider painting their bottom.


A study conducted on the denitrifying effects of sand beds noted what appeared to be a correlation between substrate depth and aquarium deaths; with death rates up to twice as high in shallow substrate tanks, and a word of caution that "it doesn't get much shallower than bare-bottom." While I've attached a link to the article, I urge caution in reading too much into the study, as this was not the focus of the actual research.

Feature Article: An Experimental Comparison of Sand bed and Plenum-Based Systems: Part 2: Live Animal Experiments — Advanced Aquarist's Online Magazine

Calcium Carbonate or Dolomite Gravel (CC): Commonly referred to simply as CC, calcium carbonate gravel used to be the most common substrate in marine aquariums, but has since fallen out of favor among hobbyists, although it is still used by some. Larger particles (usually 5 to 20mm in size) of calcium carbonate or dolomite are placed in a layer from 1/4" to 1 1/2" deep over the bottom of the aquarium. The primary reason for its fall from favor is that many believe that CC acts as a trap for uneaten food and debris and turns the substrate into a nitrate factory. Others simply do not care for the look of CC. If the CC bed is properly maintained through regular siphoning and cleaning, it is no more of a nitrate factor than any other substrate. Calcium carbonate and dolomite are both hard substances that break down slowly over time releasing calcium carbonate into the water, helping to maintain calcium levels and buffer pH in the marine aquarium. Calcium carbonate is the same substance from which many marine inverts, such as snails and many species of coral build their skeleton. Dolomite, although similar in appearance to CC is less soluble and breaks down slower as a result.

(Photo courtesy of Paul Baldassano)​

Crushed Shell (CS): Another substrate that has found some small amount of favor among hobbyists is crushed shell. Typically composed of the shells of assorted types of shellfish, CS is generally smaller than the particle size of CC and is generally more aesthetically pleasing to hobbyists, especially those who are familiar with shell-covered beaches. Like CC the CS breaks down, releasing calcium carbonate into the water, however, because it is not as hard as CC or dolomite, it breaks down and dissolves much faster. Additionally, the fine shell pieces in the uppermost layer quickly color up with coralline algae, just as the shells of snails and hermit crabs in your aquarium do. Like the CC if not properly maintained through regular siphoning, the crushed shell can become a nitrate factory as debris and fish waste break down.


Sand: Generally the favored substrate of today's modern reef aquariums, many feel that sand gives the marine aquarium a much more natural look. Additionally, the sand bed provides a place for the growth of micro-fauna and bacteria which aid in the biological filtering of the marine aquarium. Sand is used to cover the bottom of the aquarium to various depths and now is available in a variety of colors (from pink to black), size (very fine "sugar sand" to large grains) and name brands. It is generally recommended to use aragonite sand, so that it, like the CC can bread down slowly over time adding calcium carbonate to the water and helping to buffer pH. Silicate-based sand (usually referred to as play sand) should be avoided; it compacts readily, creating a concrete-like substrate and releases silicates into the water which can cause diatom blooms. Properly setting up any sand bed requires the introduction of bacteria and micro-fauna through the introduction of true Live Sand (not the bagged stuff purchased off the shelves from your LFS which at best contains only bacteria). Some of the disadvantages of a sand bed include sandstorms in the event of too strong of a current within the aquarium and sand being dropped onto LPS polyps. A sand bed is required to properly maintain certain species of fish and invertebrates, however care should be taken in the selection of livestock for the marine aquarium with a sand bed. Some critters, such as Diamond Watchmen gobies and sand-sifting sea stars, can quickly consume all the micro-fauna and bacteria in the sand bed in a smaller tank, thus causing the sand bed to become inert and no longer function for biological filtration. Once they have consumed all the micro-fauna, these animals will often slowly starve.

​

Shallow vs. Deep Sand beds: Generally speaking, 1/4" to 2" is considered to be a shallow sand bed (SSB) and 3 1/2" to 6" is considered a deep sand bed (DSB). Generally the area between the two is considered to be an unsafe zone, not quite deep enough for anaerobic bacteria to establish and carry out denitrification, but too deep for aerobic bacteria to be present, thus allowing the build-up of toxic wastes in the form of hydrogen sulfide gas which can be released if the sand bed is disturbed.
(Your photo of a shallow sand bed aquarium here)

It has generally been accepted that SSB, like CC, maintain oxygenated water throughout the sand bed and therefore must be maintained by siphoning, generally on a monthly basis. While DSBs on the other hand have an anaerobic area (typically in the bottom inch or two) very similar to Live Rock, in which anaerobic bacteria are able to establish to help break down nitrates. The DSB requires little to no regular maintenance (some do regularly siphon or stir the top inch or so). Recent research however indicates that both shallow and deep sand beds function in converting organic waste into free nitrogen gas. I've attached a link to the two articles that report these finding below.

Feature Article: An Experimental Comparison of Sand bed and Plenum-Based Systems. Part 1: Controlled lab dosing experiments — Advanced Aquarist's Online Magazine

Feature Article: An Experimental Comparison of Sandbed and Plenum-Based Systems: Part 2: Live Animal Experiments — Advanced Aquarist's Online Magazine

Alternative Materials: A growing number of individuals have also began experimenting with a number of different alternative materials in place of going bare-bottom. Starboard or Corian is one of the more popular alternatives. These materials have similar benefits to BB tank, in that they are easy to siphon off detritus and wastes, and one never has to worry about stirring up sandstorms or clearing sand from LPS polyps. They have the additional advantages of having something in place to absorb a heavy impact in the event of the collapse of rock work, and they lack the sterile look of a BB tank. The lack of substrate however, again means the hobbyist is gaining no natural filtering benefit from the substrate, and is unable to keep any sand-dwelling inverts or sand-sifting fish. Additionally, as with the BB, regular maintenance is required, as accumulated debris blowing around on the bottom can be unattractive, as can the board itself. Further as with the BB, refugium lights on a reverse cycle can shine through from the bottom, so consideration should be given to painting the bottom of the tank.

 

[lapin]

I was reading about the animals eating all of the bacteria and microfauna. I was planning on adding those things back to the tank every few months by using a refugium and some of the live bottled products offered today. Will this work?

Yes you can add those things back in your tank from a fuge and/or a bottle.
Most bacteria and micro fauna we want in our reef need a surface to grow upon. If you have plenty of that surface, its hard for tank critters to eat everything. If you have no sand or rock, just the glass, then you will not have much life.

 

[Tom Giddens]

I was referring to the part that said the sand sifters would consume everything and then starve. I will have rock, live sand, and refugium

 

[lapin]

Certain sand sifters such as stars will eat everything in the sand bed and starve if no food is avail. It really depends on how many critters you have and the amount of food avail. Sand sifting fish will usually eat other things as will snails. Usually the older the tank the more natural live food is in the system. Pods are one thing that once you introduce them they siould be there forever unless you have a too many fish and they eat them faster than they can reproduce. Then supplimental feeding will need to be done. A fuge is a good way to dose the needed live foods. The population will find its way to the tank unless filters prevent this.

 

[Tom Giddens]

So it would not hurt anything to add more pods and bacteria from time to time?

 

[FGourdin]

So it would not hurt anything to add more pods and bacteria from time to time?

Definitely would not hurt to add pods periodic!ally, particularly if you have consumers such as mandarins. I don't think it would hurt to add bacteria ever so often, but question whether it really helps any thing except in a new cycling tank. Established tanks probably reach a bacterial steady state and doubt you influence that state much with the addition of more bacteria.

 

[AlbertaBound]

This may be a stupid question, I recently purchased a 180 gallon tank. The plan being to put 2 lion fish (1 Pterois volitans and 1 Pterois radiata). Was thinking about going with a SSB. My question ks whether or not I NEED live rock or if I can use dry rock. I live in a remote city in Canada and finding live rock that will ship here is difficult to find to say the least. Any and all help is greatly appreciated.

 

[beaslbob]

This may be a stupid question, I recently purchased a 180 gallon tank. The plan being to put 2 lion fish (1 Pterois volitans and 1 Pterois radiata). Was thinking about going with a SSB. My question ks whether or not I NEED live rock or if I can use dry rock. I live in a remote city in Canada and finding live rock that will ship here is difficult to find to say the least. Any and all help is greatly appreciated.

My highly controversial unproven, experimental idea is that you don't need live rock or live sand. All those can be done with inexpensive macro algaes best in a refugium. That refugium can just be a simple tank partition to provide an small area free of fishes to protect the macros.

But that's just me and my .02

 

[CHUCKB973]

Great article! Now to decide bare bottom or shallow sand bed

 

[Daniel@R2R]

I tried going bare bottom for a minute, but I couldn't commit. I like sand.

 

[anon9896]

The link
Feature Article: An Experimental Comparison of Sand bed and Plenum-Based Systems: Part 2: Live Animal Experiments — Advanced Aquarist's Online Magazine
seems to be dead or the website might be down but it gives a malware alert wich is uncomon