DSB Related Journals, Newspaper Articles, ETC...

[Bomber]

Where's it going to go Mike? and in what form?

Look at the thread in Randy's forum, we were discussing fractions, dilution, and what takes place when you use remote filters.

[Bomber]

BTW Randy - Thanks!

I couldn't have found papers that proved my point better. Thank you

Most of those papers deal with polluted, eutrophic, or just plain toxic waters and that's exactly what happens.

[Shoestring Reefer]

I'm aware of all that, Bomber. Don't forget macro.

I'm talking about the paper and how it contradicts Dr. Ron.

[Randy Holmes-Farley]

Short answer, yes nitrate can be limiting. You just don't want that to happen in a reef tank.

OK

I thought I saw you write:

"--------------------------------------------------------------------------------
Originally posted by Bomber
Not necessarily.

We know that phosphate and phosphorous compounds are limiting in marine environments.


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While I accept this to be true, I don't know technically why this is true: is it because of dilution, consumption, lack of supply, or ??? (or some combination thereof)?



It's the combination.

There are things in marine environments that "fix" nitrogen compounds. Cyano for instance, but there are other bacteria that will do that also. They take nitrogen literally out of thin air, and introduce it into the marine environment. As long as you realize that, you understand that nitrogen/nitrates can never be limiting.

Plants in particular, need two foods. Nitrogen and phosphorous.

The only one of those two that can be limiting is P."
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BTW, if P is at natural level, and nitrogen is low enough to be limiting, why do you believe that is a problem?

[Bomber]

I know I know

But we can't be all over the place. We're talking about aquariums and what conditions are most likely in aquariums. That's why I was trying to stay away from open ocean conditions, and I just wasn't ready to go the whole sewer thing. I was trying to soft peddle it a little.

In the examples you gave, only one "open ocean" fits that criteria. The rest are not "natural levels" but range from sewer to toxic conditions.

At least I think, I only read the intro's. LOL

[TurboRook]

Couldn't the necessary N be sequestered from nitrogen gas introduced through aeration until it reaches a balance with the available P in the system? I imagine many bacteria and algae could have processes to do this.

[Randy Holmes-Farley]

No algae can do that, in the strict sense of what an algae is (AFAIK). Cyanobacteria can, but are themselves sometimes limited (say, by iron in the first article that I posted: Iron and phosphorus co-limit nitrogen fixation in the eastern tropical North Atlantic).

[shred5]

Originally posted by Bomber
I know I know

But we can't be all over the place. We're talking about aquariums and what conditions are most likely in aquariums. That's why I was trying to stay away from open ocean conditions, and I just wasn't ready to go the whole sewer thing. I was trying to soft peddle it a little.

In the examples you gave, only one "open ocean" fits that criteria. The rest are not "natural levels" but range from sewer to toxic conditions.

At least I think, I only read the intro's. LOL

Wow but some of those links you guy posted are ok ?.. They dont even mention what type of sediment.. could be anything..That one i just read was fresh water?

Dave

[Bomber]

Dave it's the same process. Adding salt does not make it magic.

Bacteria really don't care what "sediment" you have either. If shrimp poop is deep enough or in the right condition to establish anaerobic/anoxic/aerobic

[staunched]

all i can say is im glad i setup my berlin system substrate free. i was however thinking of putting a dsb in a fuge i just built. would a substrate free fuge full of caluerpa taxafolia do the job? id rather stay away from the dsb if pos by the looks of it. anyways great thread guys. much appreciated/
stauncho

[wasp]

When I went BB I retained a DSB in my newly setup fuge, but it did collect detritus, I have now removed that also.
Have to say though, that ever since I have had problems growing macro algae, just won't do very well.

[Bomber]

Trophic States

Oligotrophic
Clear waters with little organic matter or sediment and minimum biological activity.

Mesotrophic
Waters with more nutrients, and therefore, more biological productivity.

Eutrophic
Waters extremely rich in nutrients, with high biological productivity. Some species may be choked out.

Hypereutrophic
Murky, highly productive waters, closest to the wetland status. Many clearwater species cannot survive.

Dystrophic
Low in nutrients, highly colored with dissolved humic organic material. (Not necessarily a part of the natural trophic progression.)

Wasp, reef building hard corals like the first one. The other ones can grow macro algae.
When you hear people say that reefs are really algae reefs - blah blah - it's because of coralline algae not macros. But then either some hobby "experts" don't know any better or they are tying to mislead you on purpose.

[bluereefs]

it's because of coralline algae
What is with zooxalanthee and phytoplancton?
Why hair algae can grow in hard corals (sps) enviroment when damsells intentionaly destroy "sps" corals tops to culture algae?
Reason why are the coralline algae more dominant in clean nonpoluted hard corals(sps) enviroment is because the corals also compete for space against algae and they are more sucesfull.Because corals grow faster then algae in that enviroment they block the light for most lighting demanding algae but coralline algae prefer more shadind places and that is the reason why are the coralline algae primary type of algae in that enviroment.
Corals also have defensive mechanism against algae(why will corals have that abillity if algae can not grow in that enviroment?),corals produce anti fouling substances that inhibits growth of algae on them,porites sheed periodicaly same as some soft corals,to remove algae spores setled on their surface,some acropora use digestive filaments to kill algae adjacent to them...

[Atoller]

Originally posted by Bomber

Dystrophic
Low in nutrients, highly colored with dissolved humic organic material. (Not necessarily a part of the natural trophic progression.)

Also, Dystrophic is generally limited to standing water bodies or storm-impacted lagoons with limited tidal flushing, where the accumulated humic acid stands and reduces the pH of the water body, and oxygen is generally depleted.

Wasp, reef building hard corals like the first one. The other ones can grow macro algae.

It's not a matter of liking just oligotrophic conditions. It's where a whole host of conditions coordinate to favor the dominance of the corals. Oligotrophic waters aren't a universal thread. Many species of corals most often associated with "clean" areas are highly eurytrophic. Acropora cervicornis is a perfect example, with its most viable stands growing in eutrophic waters with algae-overgrown reefs both upstream and downstream.

It's not just about nutrients.

Oligotrophic conditions can and do grow macroalgae, especially turfs. Healthy corals can actually outcompete turfs, though.

[Atoller]

Originally posted by bluereefs
it's because of coralline algae
What is with zooxalanthee and phytoplancton?
Why hair algae can grow in hard corals (sps) enviroment when damsells intentionaly destroy "sps" corals tops to culture algae?

Several reasons. That is not hair algae, but generally turf, which is competitive in an oligotrophic environment. Damsel fish must kill the coral in order to provide the algae a place to grow, otherwise the coral would outcompete the algae (hence the formation of damselfish chimneys). Damselfish also, by their presence, fertilize the area where the algae is growing. It's long been known that fish that overnight on stands of coral provide phosphorous and ammonium for that coral's use. Same would work for algae.

[bluereefs]

It's where a whole host of conditions coordinate to favor the dominance of the corals.
It's not just about nutrients.
Oligotrophic conditions can and do grow macroalgae, especially turfs. Healthy corals can actually outcompete turfs, though.

[staunched]

friend just came up with an idea i thought id put to you guys which i thought you might be able to improve on. im sure its been trialed in the past but wanted to see what you guys think. for now i think we'll call it the fluidized sand bed system. hehe. anyways. what if you set up the all so dreaded in the world of marine canister filter. or even two for that matter with slow water movement sucking out oxygen, also creating nitrate, however then pumping the oxygen deficient water directly into a large fluidised bed filter that would have subsequently bred an aneoribic zone. ive heard the surface area and capabilities of fluidised bed filters is quite impressive. i think ultimatley if we could create an anearobic zone in a fluidised bed filter without having to pass through canister filters we'd be better off as the canisters are only going to create more nitrate along the way. basically im thinking a fluidised bed filter with an aneoribic zone would eliminate all the problems of anoxic gasses etc. are we off with the fairies here or does this make sense. a fluidised in the fuge would be soo simple

[wasp]

It's been tried.
For a system not quite what you describe, but close, check this thread http://archive.reefcentral.com/forum...ght=dsb+heresy
Your theory is sound, and is in fact used in commercial water treatment, however, in marine aquaria, this type of system has tended to allow phosphates to accumulate at undesireable levels.
Also, Red Sea put out what they call a Merlin Fluidised Filter, a kind of small version of what you describe.

[staunched]

cheers wasp. yea i like these fluidised bed filters. even for aerobic filtration. great for f/o or fowlr setups.

[vitz]

fluidized bed filters as a concept/practice were around quite awhile before red sea made their version (they weren't the first aquarium related co. to make them, either, by any means )

one word of caution about them in general- it's been my experience, while using them in fw store systems, that they can crash fairly quickly, in the event of loss of water flow (power failure, etc), and don't give as long an amount of time to correct a flow issue as a wet dry can.

when working, they are a great high capacity nitrifying filter though, as stated above

[staunched]

cheers vitz, valuable info which ill definately keep in mind.
stauncho

[jaybro]

My 90g main has a shallow sand bad (for looks and for providing my engineer gobies and orange spotted goby entertainment). However I have a DSB in my 55g sea grass refugium. To date I've had none of the problems with DSBs that are described here, however my fuge probably isn't mature enough at one year old to yet have reached these sorts of saturation levels.

That being said... Wouldn't true vascular plants, such as some of the sea grasses with a true root structure help remove phosphates/nitrates from the DSB? Do these plants with their intensive root systems pull enough phosphates out of the sand bed to take care of this problem? I have no idea of what the N/P ratio any of the sea grasses needs, nor if they get those nutrients primarily from their roots / leaves or both. I'm assuming most of their nutrient needs are met by their root structure, but that is just an assumption.

Be nice in your replies, I'm not claiming to be an expert or stating that this is the way things should be done! I'm just asking based on my own short term personal experience and trying to plan ahead to head off future problems.

[Shoestring Reefer]

I guess it makes sense that a rooted plant with a "true vascular system" (as you put it) would use organics from the substrait to feed teh "leaves"; at least, that's what terrestrial plants do. Maby aquatic plants are different.

I've not used any rooted plants in a SW tank. How long do they live? Indefinately? Do you cut them back?

I'll say it before someone else does: It's thought dy some (or most, depending on which thread you're in ) that a fuge/sump with a settling area and some regular vacuuming is better than a fuge/sump with a DSB because then you remove the waste rather than process it, and removal eliminates the chance of release back into the system.

[jaybro]

I can certainly see the logic in that. Though I'm still curious how much, if any, difference plants with root structures make in this scenario.

One thing I did leave out about my main system that relates to this discussion... I have a 100g stock tank as a sump (rubbermaid) that has the built in drain opening in the base. I've plumbed that opening to my Iwaki which is my return pump. It works somewhat effectively as a settling tank. I have two valves (directly after the Iwaki). One is to the return, the other is to a drain line that empties directly into my household waste system. When I want to do a water change, I simply close the return valve and open the waste valve (two waste valves actually, one where it enters the household waste and one by the return valve). As it pumps out my roughly 80g of water in the sump I 'sweep' most of the debris that has settled in the stock tank, out the return/waste line. I never thought about this activity in the 'barebottom settling tank' words that you've used. Though I guess that's what it's doing. The only differences are that my water changes probably aren't occurring with the same frequency that you should siphon out these settling tanks and it probably has too high of a flow through to settle as effectively as a true settling tank.

Time will tell if that's enough to prevent having to yank my DSB. I will be highly upset if I end up having to remove my sea grass tank with all it diverse and interesting life forms.

[jaybro]

My apologies for the second post, I just realized I didn't answer your questions regarding plants in a SW tank...

"I've not used any rooted plants in a SW tank. How long do they live? Indefinately?" -- Yes, if they are properly maintained they live indefinitely. Each individual plant may not, but they spread with their roots (rhizomes?) and send up new plants through the tank. Occasionally I have to go through and thin them out.

"Do you cut them back?" -- Yes, I both thin them back by removing plants that are spaced too closely and also remove individual leaves as they start to brown. If you don't remove dieing leaves they decay and put organics back into the water column. If you let them go to long without attention (I do this roughly weekly) and you have too many browning leaves they seem to become prone to disease. In my experience if you plant them carefully without harming the roots in a sand bed at least 4-6 inches deep and 6+ months old with good lighting, they grow fairly quickly and easily. All of these comments are in regards to my experience (very limited) with the sea grass that goes by the common name "turtle grass". Yes, there are many types of sea grasses and probably many types that go by the name turtle grass. No, I unfortunately do not know the scientific name but I'm sure someone will post it for me later! =}

As a side note, I got my turtle grass from www.floridapets.com. I've ordered a fair bit of odds and ends from them over the last two years and have all ways had good service and free replacements of anything that didn't handle the rigors of shipping