How deep sand beds work

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mojoreef

Reef Keeper
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The concept of a deep sand bed is to create an environment skewed to the population and growth of various bacterias. These bacterias will reduce and or cycle various elements of food/detritus/waste.
There are numerous cycles which occur in a deep sand bed, i.e.: nitrogen/phosphate/carbon/sulfur/iron and methane cycles. The cycles utilize most environmental types created by a deep sand bed. The deep sand bed can be broken down into zones. The first so is the aerobic zone (oxygenated) in the second zone is the anaerobic (depleted oxygen) and the final zone is the anoxic (devoid of oxygen).
The first zone of a deep sand bed is called the aerobic zone (oxygenated). In this zone a variety of creatures live, snails, pods, various worms and so on. But the most important critter is bacteria. In this zone bacteria will reduce ammonia to nitrite and nitrite to nitrate. This process is called nitrification and is done by the stealing of a proton or electron from nitrogen based products.
From here through the migration of worms and so on nitrate is passed down to faculative bacteria(batceria that can fix both oxygen and nitrate). As oxygen levels deplete these bacterias change from fixing oxygen to fixing nitrate. Nitrate is reduced nitrate oxide then reduced to nitrous oxide and finally reduced to dinitrogen gas. This gas is then off gassed back up through the bed and into the water column. However if there is the presence of ammonia anywhere in this is all been expectation will not occur, instead nitrate will be converted to ammonium which will then migrate up to the aerobic so and once more will be reduced to nitrite and then back through the cycle once again.
The carbon cycle basically boils down to respiration. Carbon dioxide is reduced via certain cycles to for glucose which is used as energy. This will provide a certain amount of exportation, usually about five to 10% of whatever the input is.
The sulfur cycle occurs in both the aerobic and anaerobic zones. Here the sulfate portions of food/detritus/waste our reduced to sulfur and then to sulfide. Sulfide can be reduced further to sulfide gas in the anaerobic zone. All sulfur products will not be exported but will be continuously cycled with in the sand bed.
In the phosphate cycle the phosphate portion of food/detritus/waste enters the sand bed. It is immediately attacked by bacteria trying to reduce it. With this influx of food the bacteria population will bloom. As the food begins to be reduced and is no longer available the bacteria will begin to die off, once they do this the phosphate that they had fixed is released back into solution. Here usually algae is the first organism to take advantage of this. Cyanobactor and hair algae are usually the first on-the-job, they utilize the available soluble phosphates and begin to bloom themselves, this will continue until they use up all the available food stock. Then once again they begin to die off, at this point bacteria begin to reduce the rotting algae and once again bloom. What you will see is small blooms of hair algae and or cyano appear on your sand or adjoining surfaces, it will then disappear as it is reduced. As you continue to add more and more phosphate to your tank these blooms will get larger and larger until they will not disappear.
The balance of the cycles that occur in the sand bed usually do not have an impact on its health.
The deep sand bed is usually set up by using four to 6 inches of oothlic sand. Oothlic sand is very fine and allows more surface area for the growth of more bacteria. Detrovior kits must also be added to the sand bed. These kits consist of bacteria, worms, snails, pods and so on. These critters are essential to keep the sand bed stared and allow for the migration of food products to various levels in the sand bed. Creatures such as sand stirring stars, gobies, qukes should not be used in a deep sand bed system as they will eat and deplete the smaller above-mentioned critters. Natural selection will also deplete the stock of those smaller critters over time, so these kits should be added to the sand bed every eight to 12 months.
Pros:
if set up correctly and maintained correctly the deep sand bed system will allow for good nitrification and denitrification.
A deep sand bed environment will create a good refuge for smaller organisms such as bacteria, plankton, nekton and larva. Which can be a food source for higher life forms in the immediate area.
A DSB is aesthetically pleasing to many people.
A DSB will add more microscopic diversity to your reef tank.
A DSB will facilitate the harvesting of hair algae and cyanobactor on the sand substrate and adjoining areas. If this algae is harvested it can be a source of exportation.
Cons:
Since a DSB will only export nitrogen based products if set up correctly all other products that enter it will be sunk and stored. This will put a time limit on the functional ability of the sand bed as time goes by.
Since the sand used in setting up a DSB is already saturated with phosphates in the lower regions of the bed with a pH is very low the sand will begin to melt and release these bound up phosphates back into solution. This will also occur through bacterial action. So it will become a source of phosphates as it matures.
With the use of small fine sand, the amount of water flow will be restricted to whatever will not allow the sand to stir up into the water column.

mojo
 
Very interesting, how long does a DSB stay healthy assuming the tank is maintained & what exactly is a Detrovior kit? My son in law just set up a 180 6 months ago & fights cyano & then hair & then cyano & then hair. What should his "Detrovior kit" consist of? Thanks
 
Very interesting, how long does a DSB stay healthy assuming the tank is maintained & what exactly is a Detrovior kit? My son in law just set up a 180 6 months ago & fights cyano & then hair & then cyano & then hair. What should his "Detrovior kit" consist of? Thanks

I think a detrovoir kit mainly consists of a clean up crew designed to keep the sand bed "cleaned". Could be anything from starfish to hermit crabs etc. On your son in laws tank, being only six months old means it is still young so it may still be going through a bit of a cycle. The fact that he is fighting hair algae then cyno then hair algae can be because of a lot of reasons but it all boils down to one thing...The tank has nutrient rich water ( ie increased levels of nitrates, phosphates etc). This can come from not using ro/di water, over feeding, over stocking the tank, not doing proper regular tank maintenance in terms of water changes, cleaning cartridges, sponges etc if being used or even the type of filtration methods he is using. If he's using a wet/dry filter than that is probably his source of nitrates. We'd need a bit more info on his setup to actually try and pinpoint what exactly is causing the algae issues. :)
 
Hiya Epic its really impossible to tell as it depends on so many variables, what you bioload is, how much you feed, how much you export through other means and so on. So the only thing you could assume is that if you dont have a huge bioload and you dont overfeed and you use other means to remove nutrients (skimmin, ozone, algae and so on) it will last longer then if you did it the opposite?? LOL I know not much of an answer but its really hard to figure it out.

On the detrovior kit, its basically a bunch of detroviors or in simple language things that live in the sand and eat waste and move sand. SO things like worms, mini stars, nas snails, copepods, mini clams and similar. I am not sure you sells them anymore but I am sure if you asked the sponsors they could tell ya. Also other hobbists can share this stuff with you to.

Your son in laws tank is still very young so it might be fighting the cycle still. Alot of folks think that cycling a tank is just setting up the bacterial process for denitrification, but its not just that simple, what you are looking for is balance. Let me explain.
When a tank is new and we dump a dead shrimp or what ever in to cycle, what that does is give food to the bacteria so their populations will increase, as the different bacteria reduce the product the create a biological system or tree that does the deed. But once that shrimp (or live rock with decaying material or whatever means you use) has been reduced the bacteria population will reduce with it (as they are limited to the food available) as the bacteria die off, algae is usually johnny on the spot, so now the algae absorbs the nutrients released by the dieing bacteria, and once more when the algae has absorbed what available it will then begen to die off for lack of a food source. This swing will continue until your tank reaches an equalibrium (or what hobbists call matured) which is where the population of bacteria is supported by the amount of food available to them on a consistant basis. So with a tank that young he could still be fighting that battle. so best to tell him to keep testing the water and then also testing what he is puttinf into the tank, as in top off water, the food type? and so on

hope it helps

Mojo
 
Ah krish you beat me by 4 minutes, got to work on the typing skills. One thing to remember is that detroviors, crabs, stars and similar dont really do much in the way of cleaning. Yes they will take up the waste and consume it, but they will poop back about 90 to 95% of that right back in, so not much of a gain. What they do do is to stir the sand a bit which allows for the transmission of nutrients through the bed.

Mojo
 
Ah krish you beat me by 4 minutes, got to work on the typing skills. One thing to remember is that detroviors, crabs, stars and similar dont really do much in the way of cleaning. Yes they will take up the waste and consume it, but they will poop back about 90 to 95% of that right back in, so not much of a gain. What they do do is to stir the sand a bit which allows for the transmission of nutrients through the bed.

Mojo

I'm sorry Mike lol!! Atleast your reply makes me feel like I actually know something for a change seeing you said basically the same thing :lol:
 
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I ran a DSB for about 3 years in a 20 long. It did real well until after the third year. Then, I could never get the trates below 30ppm no matter what I did, increase sand shifters, massive water changes, upgraded the skimmer. I ended up chuckin the whole thing and went bb instead.

During those 3 years my corals did REAL well and grew like weeds.
 
Yea I wouldnt dought Tike, they do produce an amount of plankton and bacteria which are both mainstays for corals. Also while the bed is functioning properly they do leach small amount of Phosphate which can help with tissue growth in corals to.

Mojo
 
Mike,

Hmmm...has me thinking about my DSB and what I should do with it (if anything)..my tank has been up and running since May 2007 and since I am fishless right now til end of February, should I do anything to my oogilite sand??..Is this tank considered "mature"?

I am noticing red algae (cynao) on the sides of the tank and on the sandbed.

the only time I get this is when my lights need changing, but i just added replacements in Sept 2010, however I am noticing a yellow tint to the lights. Next pay period I am going to replace my 10K XM bulb with 15K XM bulbs, and increase my CUC. I added 10 turbo snails which are helping on the sides of the tank, but not the sandbed. I need to add more nassarius snails and turbos AFTER I redo my aquascape which most likely will distrub the sandbed some.
 
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I have been interested in a DSB more specifically a RDSB for quite some time. Now that I have the big, well bigger, tank set up and have all new sugar sized sand in there I have been trying to figure out what to do with my old sand. My immediate thought is a RDSB. Got any pointers? I don't want to toss it, but can't use it because it is too large for my sharks....too rough, but this sand has been alive and in a running system for 3 years or more. I left an inch or so of water in my old tank when I made the move the day before yesterday and as of last night I have pods everywhere in my old tank. I really want to utilize my old sand but I have a ton of flow in my sump. To the tune of 3600gph in a 30g sump.

I was thinking of rinsing the dirt a bit with tank change water then tossing sand in a sock of sorts then dropping it into my sump. What potential negative effects could I be facing?
 
Hmmm...has me thinking about my DSB and what I should do with it (if anything)..my tank has been up and running since May 2007 and since I am fishless right now til end of February, should I do anything to my oogilite sand??..Is this tank considered "mature"?

Oh yea that is mature for sure. If it was me NC2WA I wouldnt do anything with it unless it was showing some bad signs. Again doing the testing I mentioned above will give you the answers, or when things get totally out of hand algae bloom wise.

The fellow who really pushed DSB's into the hobby (Dr. Ron) intensoin was to have the bed as a nutrient recycler and then use algae as the exporter, he just didnt really tell anyone about the algae exporting until a few years later when pressed on it. So if you have one, let it do what it was designed to do. once it looses that capability then it will be time to change things

mojo
 
ReefLogic again I dont see the benefit of a remote sand bed, so why not use it as a kind of refugium?? you can then let the bugs populate to feed you tank, you could use algae as an export method? use it for keeping fish in that are getting picked on?? maybe throw some shrimp or some kind of fish for breeding? or fish that can survive in the main display?? stuff like that.
I was thinking of rinsing the dirt a bit with tank change water then tossing sand in a sock of sorts then dropping it into my sump. What potential negative effects could I be facing?
Nope bad idea. When you create an enviroment that has very fast well oxygenated water running over a substraight (sand, rock, bioballs or similar) you have just made a great for bacteria to setup shop, problem is that the only bacteria that can live their are the kind that have and end product of nitrates, so you will end up with that.


Look when it come to the different types of means that we use to deal with waste and similar thay all have their draw backs. If you go with BB then your doing more real time maintainence, go with algae you run the risk of it going sexual, or having to harvest it or that it might spore and get in the main, sediment systems kind of our a enjoy now and then pay later. So all have their goods and bads, but it is always better to know exactly how they work, then it just becomes a personal choice

Mojo
 
Mojo, as always I appreciate your input. You are very knowledgeable and I for one really look forward to reading what you have to say.

So....what to do with my old sand? It is too rough for my new inhabitants and I don't really want a bunch of tanks running. I kinda like the whole "one tank" thing ATM. Is it possible to incorperate my 14g into my current sump setup? Another question is about recommendations for an ATO.
 
Mike,

Thanks. That was my plan. But since I am going to reaquascape it next week I thought I would ask now.
 
reeflogic sure you can set up a smaller tank that could be incorporated into your sump, but that just a matter of logistics. Just make sure you only us the top layer of your old sand.
 
if you want to reuse it, I would rinse it THOROUGHLY, as in its present form it would contain high amts of ammonia, nitrites, etc.
 
hmm....I feel I should just offer it as seed sand to anyone in need. As stated it is way too rough for my current system which is why I wanted to add it into my sump....to keep the benefits of it.

thank you guys for your patients and input.
 
you could, but I would stipulate it needs to be rinse before you add to the tank..basically this sand after it is rinsed is "new"and will need get 'live' again.
 
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