what is all of this dsb crash talk i read?

[gregt]

1. Can a DSB be used to complete the nitrogen cycle? Yes. My DSB is living proof of that. Are their other methods available? Yes.

2. Have average aquarists and experts alike used the DSB method safely over a long period of time? Yes.

3. Can system crashes be conclusively attributed to the failure of DSB's? Not Yet.

I care about the answer to a different question than you do.

1. Can I accomplish the same nitrification without the hassles and expense of a DSB. Yes.

[Bomber]

Originally posted by Bomber
With coffee in hand, he slowly approaches the key board

You guys certainly like to get carried away, don't you? I've never said no sandbeds under any conditions.

For one thing, maybe we need to define what eutrophic really means.
""Having waters rich in mineral and organic nutrients that promote a proliferation of plant life, especially algae.""

It does not mean a "dead zone". When a area goes eutrophic, there is still plenty of life there. It's just that the life that's sensitive to phosphates is either dead or long gone. You still have crabs, starfish, anemones, some sponges, and some types of corals, etc - anything that's not bothered or will tolerate it. You can even set up a "eutrophic" aquarium - which a lot of you have - and there's absolutely nothing wrong with that. Mushrooms, leather corals, some anemones, etc - a beautiful eutrophic tank.

The only problem is, when you get into housing things that will not tolerate eutrophic conditions, like reef building hard corals, some sponges, gorgonians, etc. They will not tolerate eutrophic conditions in the wild and they will not tolerate eutrophic conditions in a aquarium either.

One more time!

[Randy Holmes-Farley]

Going back to an earlier post of yours:

But not one single person has presented one single scientific paper proving anything that I've said was wrong. IN OVER A YEAR


I've always been open to anything anyone wants to post - show me the proof. Show me a scientific - not hobby - paper that says anything different than I'm saying.

As far as understand, the papers that you have posted show that phosphorus can get into and also get out of sediment. I don't dispute that. I doubt if anyone does.

It is the connection of this mechanism to reef tank crashes when sand beds get old that seems to be the matter of discussion.

I don't see any papers either way that say anything about this mechanism being important or not in reef aquaria, so I can't "prove you wrong" with literature references.

I don't doubt that some reef aquaria may become more eutrophic over time when any of the nutrient export mechanisms are not working as well as they might once have, including sand.

[Bomber]

It is the connection of this mechanism to reef tank crashes when sand beds get old that seems to be the matter of discussion.
I don't see any papers either way that say anything about this mechanism being important or not in reef aquaria, so I can't "prove you wrong" with literature references.

[b]Do you wait until studies on different chemicals are done in a "reef aquarium" to see how they work? or do you just know that when you put this chemical in salt water it's going to work a certain way?[b]

I don't doubt that some reef aquaria may become more eutrophic over time when any of the nutrient export mechanisms are not working as well as they might once have, including sand.

Exactly, what part of what I've been saying are you not understanding?

Take your aquarium for example. It is a perfect example of how you would set up a model to study a eutrophic system. Actually, it's exactly the way these models are set up and the reason you're not concerned with phosphates.

Do you remember when we were trying to figure out how much water I would change in my aquarium?

X amount of water in the tank - X same amount of new water If I pump it in at the same rate I pump it out, what percentage have I changed when I run out of new water?

In order for your algae filter to work, you will have a higher concentration of what it's taking out in the main system at all times. QUOTE]

[Randy Holmes-Farley]

Do you wait until studies on different chemicals are done in a "reef aquarium" to see how they work? or do you just know that when you put this chemical in salt water it's going to work a certain way?[

Actually, I can provide literature articles that demonstrate that hydrogen sulfide released from sediments DOES kill organisms in marine systems. And yet you are quick to discount that as a possibility. Why the double standard?

For example:


The sulfide tolerance of milkfish and tilapia in relation to fish kills in farms and natural waters in the Philippines. Bagarinao, T.; Lantin-Olaguer, I. SEAFDEC Aquaculture Department, Iloilo, Philippines. Hydrobiologia (1998), 382 137-150. CODEN: HYDRB8 ISSN: 0018-8158.

Abstract

Fish kills of milkfish Chanos chanos and tilapia Oreochromis spp. now occur frequently in brackish, marine, and freshwater farms (ponds, pens, and cages) in the Philippines. Aquafarms with high org. load, limited water exchange and circulation, no aeration, and high stocking and feeding rates can become oxygen-depleted and allow sulfide from the sediments to appear in the water column and poison free-swimming fish. The sulfide tolerance of 2-5 g milkfish and 5-8 g O. mossambicus was detd. in 25-L aquaria with flow-through sea water (100 mL min-1) at 26-30° and sulfide stock solns. pumped in at 1 mL min-1. Total sulfide concns. in the aquaria were measured by the methylene blue method and used in the regression against the probits of % survival. Four expts. showed that the two species have similar sulfide tolerance. In sea water of pH 8-8.5, about 163±68 mM or 5.2±2.2 mg l-1 total sulfide (mean ± 2 se) or 10 mM or 313 mg l-1 H2S was lethal to 50% of the fish in 4-8 h, and 61±3 mM total sulfide or 4 mM H2S in 24-96 h (to convert all sulfide concns.: 1 mM = 32 mg l-1). Earthen pond bottoms had 0-382 mM total dissolved sulfide (mean ± sd = 54±79 mM, n = 76); a tenth of the samples had >200 mM. The water column may have such sulfide levels under hypoxic or anoxic conditions. To simulate some of the conditions during fish kills, 5-12 g milkfish were exposed to an abrupt increase in sulfide, alone or in combination with progressive respiratory hypoxia and decreasing pH. The tests were done in the same flow-through set-up but with sulfide pumped in at 25 mL min-1. The lethal concn. for 50% of the fish was 197 mM total sulfide or 12 mM H2S at 2 h, but 28-53 mM sulfide allowed fish to survive 6-10 h. Milkfish in aquaria with no aeration nor flow-through sea water died of respiratory hypoxia in 5-8 h when oxygen dropped from 6 to 1 mg l-1. Under respiratory hypoxia with 30-115 mM sulfide, the fish died in 2.5-4 h. Tests with low pH were done by pumping a weak sulfuric acid soln.
at 25 mL min-1 into aquaria with flow-through sea water such that the pH dropped from 8 to 4 in 5 h. Under these conditions, milkfish died in 7-9 h when the pH was 3.5. When 30-93 mM sulfide was pumped in with the acid, the fish died in 2-6 h when the pH was still 4.5-6.3. Thus, sulfide, hypoxia, and low pH are each toxic to milkfish at particular levels and aggravate each other's toxicity. Aquafarms must be well oxygenated to prevent sulfide toxicity and fish kills.

[Bomber]

Originally posted by Randy Holmes-Farley
It is the connection of this mechanism to reef tank crashes when sand beds get old that seems to be the matter of discussion.

They act exactly like they do in nature. They have to. You expect them to act exactly like they do in nature to take care of nitrogenous compounds and that's why people use them. Almost without exception, everyone says "I use it to get rid of nitrates".

Because of the bacteria that's in them, that causes them to perform denitrification. It's those same exact bacteria, those same exact conditions, that cause the phosphate problems.

It's the exact same process in a aquarium that goes on in nature, if not, you wouldn't have denitrification. AND if you have denitrification - you have a phosphate sink that leaks.

[Bomber]

Originally posted by Randy Holmes-Farley
Actually, I can provide literature articles that demonstrate that hydrogen sulfide released from sediments DOES kill organisms in marine systems.

Big whoopie!



I told you and you already know it. You would be driven out of your house by the smell long before it did any damage to your tank.

[Bomber]

Of course that would explain all the posts >

"Help, what happened?? My whole house smells like a cow farted in it!"

[Randy Holmes-Farley]

You would be driven out of your house by the smell long before it did any damage to your tank.

Are you sure that is true?

Are you sure that the many nonvolatile sulfide species that rapidly form, like FeS, are not toxic enough when ingested that they couldn't be stressing corals?

[Bomber]

Look it up. I'm sure but you're not.

We work with these models all the time. I even set up a separate greenhouse for them to work in cause we have some employees that wouldn't go in the main buildings when they are doing that.

[gbr]

I think I am starting to understand a little now...done more reading.

you have a phosphate sink that leaks

So I would eventually see slowly increased levels in my P tests? Is the "crash" then caused by not keeping up with the testing? As "crash" was defined earlier

it (the aquarium) may begin to decline in overall health

At that point I just need to keep the P out of the water column right?

But...I guess I see the point of not wanting to do that if you don't have to.

So it looks to me like I either have to work at keeping nitrates down or work at keeping phosphates down. Isn't that kind-of even?

[Bomber]

Explain it to me one more time.

I say DSB's leak phosphates.

You say they leak hydrogen sulfide.

Ron says they leak heavy metals.

The benefits are what again? I forget.

[Randy Holmes-Farley]

Look it up. I'm sure but you're not.

We work with these models all the time. I even set up a separate greenhouse for them to work in cause we have some employees that wouldn't go in the main buildings when they are doing that.

I have been unable to find any data on the toxicity of corals to various sulfide species.

[Bomber]

Originally posted by gbr
So I would eventually see slowly increased levels in my P tests?

Nope

You're testing for the same P that water soluble highly reactive P. You won't see the build up. By the time you see water soluble P, it's because it has no where else to go.

[Bomber]

Originally posted by Randy Holmes-Farley
I have been unable to find any data on the toxicity of corals to various sulfide species.

Hello! You asked about smelling it before it did any damage. Why are you looking up toxicity to corals?

Look up toxicity to your nose.

[Bomber]

Originally posted by Randy Holmes-Farley
Are you sure that the many nonvolatile sulfide species that rapidly form, like FeS, are not toxic enough when ingested that they couldn't be stressing corals?

What happens to form these iron sulfides, where does it come from, and how does that effect phosphate?

Iron sulfides cannot bind phosphate. Therefore, when iron oxyhydroxides are converted to iron sulfides during sulfate reduction, phosphate can be released to the water column.

[DonJasper]

Originally posted by Bomber
With coffee in hand, he slowly approaches the key board

For one thing, maybe we need to define what eutrophic really means.
""Having waters rich in mineral and organic nutrients that promote a proliferation of plant life, especially algae.""

Measurable, gradual. No initiation into a 'scientific paper reading society' priesthood required. LOL!!! If that's what's called a DSB crash - fine. The only quibble I have is over the verb. I'd think the process of eutrophicing ... eutrophness ... eutrophy -whatever! - would be more accurately described as a 'fade' rather than a 'crash'. But I've got better things to do with my life than argue if stones are classified gravel, pebbles, sand or shingle.

But no fair calling a sudden mass death incident with no post eutrophication a 'DSB crash'. (sigh) Yea and people should call them zoanthids and not zoo's.

I intend on using that as a definition of a DSB crash, with all the proper attributions blah blah blah. – the next time someone else bring up DSB’s. The DSB's only got itself to blame for limiting itself to nitrate reduction, I’m not interested in defending it’s limited abilities.

[Bomber]

Originally posted by DonJasper
But no fair calling a sudden mass death incident with no post eutrophication a 'DSB crash'.

LOL I call that a train wreck Don.

I would just change it to "pre" eutrophication.

[DonJasper]

Originally posted by Bomber
LOL I call that a train wreck Don.

Really? With my recent luck - I call it Saturday.

"Hummm. I'll bet spilling that kalk sludge into the tank wasn't the most careful thing I've done today. Ok, one more item on the Do Not Do Again List. Guess I'll have to be starting a third page pretty soon."

[Bomber]

Don't you get it Randy? You don't need a model or studies specifically targeting aquariums and what happens in them. The simple fact that denitrification is taking place tells you all you need to know.

Denitrification is not a straight line, linear event.

The same bacteria that make denitrification possible, the same exact conditions that make denitrification possible - is the exact same thing that causes you problems. All these problems are a direct result of denitrification taking place in your aquarium.

[Randy Holmes-Farley]

The same bacteria that make denitrification possible, the same exact conditions that make denitrification possible - is the exact same thing that causes you problems. All these problems are a direct result of denitrification taking place in your aquarium.

You mean the problem being that you are leaving phosphate behind? I've always worried about that.

[Bomber]

P is essential for life, right?

Denitrification is not a linear event.

[Randy Holmes-Farley]

I think I'm talking to mystic from India.

[Bomber]

A increase in water column P is a direct result of anoxic conditions. The binding of P by iron oxyhydroxides by their conversion to iron sulfides during sulfate reduction guarantees the release of P. Iron sulfides cannot bind P.

This is all just part of the denitrification process. It's where you got your hydrogen sulfide from.

All these things are just part of the denitrification process. You can't have one without the other, and having one - guarantees that you have them all.

Again, that's why it would be damn silly to study this in aquariums. We already know every thing about this we need to know. Having one, guarantees that you have them all.

[Bomber]

I'm trying my best to make you think!