Deep Sand Bed -- Anatomy & Terminology

[joe perry]

A few questions if you don't mind. I read somewhere that one of the things carbon dosing causes is a yellow precipitate to form. I think the Germans call it gelbstoff (yellow stuff). Wikipedia says the yellow stuff is actually tannins. Might this gelbstoff actually be a buildup of sulfur? Also, I read about a nitrate reactor that uses sulfer based media. This reactor apparently is supposed to have a very slow flow rate. I'm guessing that the sulfur-reducing bacteria that TMZ wrote about are consuming nitrates in this reactor? If so, does this happen somehow without the production of hydrogen sulfide?

 

[tmz]

Gelbstoff as used in this context is a type of organic matter (posses C and H atoms) (there are millions of organic compounds ) The organics accumulate over time and some have a yellow cast. The gelbstoff are removable with granulated activated carbon. They are not sulfur.

The bacteria that consume sulfur(S) in hypoxic areas( low oxygen with nitrate) are not the same as those that reduce sulfate(SO4)
in anoxic areas ( no oxygen or nitrate)

The bacteria in a sulfur denitrator use the sulfur as food and the oxygen in nitrate for energy : 2 H20 plus 5 S plus 6 NO3( nitrate) then bacterial activity then 3 N2 (nitrogen gas) plus 5 SO4 plus 4 H +.
They do not reduce sulfate. Sulfur denitrators often become anoxic when nitrate levels drop to 0 and do produce hydrogen sulfide when the sulfate reducing bacteria take over.

 

[tmz]

Gelbstoff as used in this context is a type of organic matter (posses C and H atoms) (there are millions of organic compounds ) The organics accumulate over time and some have a yellow cast. The gelbstoff are removable with granulated activated carbon. They are not sulfur.

The bacteria that consume sulfur(S) in hypoxic areas( low oxygen with nitrate) are not the same as those that reduce sulfate(SO4)
in anoxic areas ( no oxygen or nitrate)

The bacteria in a sulfur denitrator use the sulfur as food and the oxygen in nitrate for energy : 2 H20 plus 5 S plus 6 NO3( nitrate) then bacterial activity then 3 N2 (nitrogen gas) plus 5 SO4 plus 4 H +.
They do not reduce sulfate. Sulfur denitrators often become anoxic when nitrate levels drop to 0 and do produce hydrogen sulfide when the sulfate reducing bacteria take over.

 

[PaulieReef]

Very useful information Thanks!

 

[GT3]

I am new to this forum, it is always nice to hear feedbacks from others, I like hearing opinions and share mine to improve everyone's knowledge.

But thanks for your not so generous comment telling me EVERYTHING I posted is wrong. Obviously you planned and spent hours researching to correct what you think are my mistakes, and conducting the layout to let others think I am bluffing.

I find many doubts in your reply, there are absolutely no source of where your information came from.

If you are a professional(please state). I shall respect your knowledge, otherwise I am up to this healthy debate, as I will find a lot of information from my University to support and improve my statements.:hammer:

 

[tmz]

There is nothing to debate. My response based on years of experience and study was extemporaneous , simplified and correct. My comments were necessary to correct false information for the sake of others and were offered in as gentle and kind a way as possible. In any case the information is out there now and folks can judge it and or research the facts if they wish.

 

[tmz]

Very useful information Thanks!

You are welcome; glad it was helpful.

 

[rivoth]

One useful study I found came from an an attempt to determine whether a plenum system was useful for a deep sand bed. As part of this study they found that every type of sand bed they tested: deep, shallow, coarse or fine would reach nitrate equilibrium with a very heavy daily dosage of ammonia. The differences in when they reached equilibrium were pretty minor compared to the sampling noise.

So the bottom line is you are going to get a lot of filtration benefit from just about any type of sand bed that you put in. Apparently having a deep enough bed for a classic anoxic zone is not necessary. Which means the theorists need to come up with some new theories.

http://www.advancedaquarist.com/2005/6/aafeature

 

[Paul B]

Rivoth, thank you for posting that link. I like this part

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.

And this part.

We urge hobbyists to develop a good 'BS' detector that will allow you to question information presented to you without any experimental evidence to support it.

I have been telling hobbiests this for years.
I personally think DSBs don't do much of anything but that is of course just my opinion.
But if they work so well, why does everyone using them have to change water to reduce nitrates? I wonder. :strange:

 

[rivoth]

I don't need to change water to reduce nitrates in my DSB, and I feed pretty regularly to keep my Goniopora happy. I do like the fact that my deep sand bed is full of life, that's the sort of thing that keeps me interested in the hobby. Except for wanting to put in sea grass at some point, I probably would have done just as well with 3" as with the 6" that I have.

 

[Paul B]

I probably would have done just as well with 3" as with the 6" that I have.

I am sure you would have

 

[Lynnmw1208]

I have a question for you guys. I want to have at least 4" of tropic eden reeflakes in my tank because I want a jawfish. that being said, how do I keep the sand from getting the buildup of toxic substance on the bottom? I want to keep a sand sifting goby and burrowing snails as well, will that help keep things stirred up a bit?

I don't really want to use the sand for the benefits of the DSB but rather just for aquarium inhabitants.

 

[wiseman79]

New to saltwater (less than a year) so please be gentle, I have been reading through this thread for nearly an hour. I have a DSB in my 90g, it slopes in depth across the width of the tank from ~2.5" to ~5.5". A question I have to determine if it is indeed anoxic (so I can put the wealth on info in this thread in context to my tank), is the presense of coraline visible at the glass all the way down through the depth of the bed. Not heavy, but a purple tinge present in striations all the way down. Is this fact relavent to the equation at all or am I focusing on a non issue. Thanks.

 

[pigmagnet]

my deep sand beds look great but are a ton of work. glass bottom is easier, and less beneficial.

 

[tmz]

Coraline algae would not thrive in anoxic areas. Black spots of sufide deposits are a visual indicator.

Personally, I like deep sand beds in some situations. They need replenishment with live sand periodically(around 10% every 6 mos or so) to keep them live and well channeled. Otherwise, they clog overtime( 1 to 3 yrs usually) and flow to the deeper areas is impeded resulting in a potential for anoxic areas. Drops in ph in the sand may also release bound metals that may have accumulated. Sand sifting gobies keep it clean but they spray sand about and may decimate bacterial populations. Nasuarius snails do some beneficial sifting, ime.

 

[cloak]

Coraline algae would not thrive in anoxic areas. Black spots of sufide deposits are a visual indicator.

Personally, I like deep sand beds in some situations. They need replenishment with live sand periodically(around 10% every 6 mos or so) to keep them live and well channeled. Otherwise, they clog overtime( 1 to 3 yrs usually) and flow to the deeper areas is impeded resulting in a potential for anoxic areas. Drops in ph in the sand may also release bound metals that may have accumulated. Sand sifting gobies keep it clean but they spray sand about and may decimate bacterial populations. Nasuarius snails do some beneficial sifting, ime.

Couldn't this just be accomplished by mixing the grain sizes? I forget which direction they go, but wouldn't the larger grains sink while the finer ones would rise? I would think the sandbed be in constant motion, almost breathing so to say, no?

Thanks.

 

[tracyk859]

Hi, I am Tracy . I am a new member of forum. Would a newcomer be warmly welcome here? Good day you guys!!!

 

[Aquarist007]

I agree with PaulB that dsb's are not that effective at reducing nitrates. There are much more effective ways such as refugiums with macro algae
lately I have been experimenting with np biopellets and am really impressed by them so far. Their almost immediate affect on water clarify and stimulation of corals is worth it alone

 

[tmz]

I think well maintained deep sand beds with enough flow to the deeper areas can do a fine job encouraging anaerobic respiration of NO3. They do ,however require significant work and there are alternatives including shallow beds, organic carbon dosing, denitrators, refugia ,etc.

 

[rivoth]

Why would you say there is significant work involved in a deep sand bed? I've had one for 2 1/2 years and if anything it has saved me work. You put fine grained sand in, you cycle your tank. Use a bit of intelligence in your water flow so that the pumps are blasting water at the top of your tank, and the undertow returning to the pumps is what keeps your sand bed well circulated.

After the tank is fully cycled order a couple pounds of sand with live critters in it from Inland Aquatics. Add a fighting conch for every 2 square feet of exposed sand. A self sustaining population of Cerith snails would be nice. It's also very helpful if you have Amphipods and some Benthic Copepods. Feed your tank food regularly and watch the lower sand behind the glass start to fill with fine tunnels. Once you start seeing some Cyano on the sand then add either a Tiger Tail Sea Cucumber or a one of the smaller "Holothuria floridana" sea cucumbers depending on the size of your tank. Remember, all these critters require food, don't starve your tank.

Then pretty much forget about the sand bed, it will be fine and form a contributing helpful part of your tank ecosystem. It's not the only way to run a reef tank, but it is a very good way to run a reef tank. Don't expect it to keep you at zero nitrates. What it will do is keep your nitrates from climbing higher and higher which amazingly enough is all that's required. It will also allow you to feed your corals a lot of food without extra maintenance work. That's because all that life in the sand forms the best clean up crew ever. It also provides live food to your corals, something that's in short supply in home aquariums. Now if you are not a person who likes seeing bugs and worms then run, don't walk, over to that corner with the bare bottom folks.