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Discussion Starter · #1 ·
Some funny misconceptions I've read about DSB's

#1 That a lot of thought and "scientific" research went into developing DSB filtration.

#2 That DSB's are mimicking nature.

#3 That reefs rely on sand beds and grass beds for filtration.

#4 That reefs rely primarily on bacterial filtration.

#5 That denitrification does not occur in a shallow sand bed.

#6 The ocean naturally protein skims.

#7 That DSB's are some how producing all this food for corals. (partly true but not the way people seem to think)

#8 That natural reefs are not bacterial driven also.

#9 That DSB's are something besides just another bacterial filter.
 

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Jerel, where's is the tenth commandment?:D Jerel don't the reefs rely on the sand beds and grass beds and all the bacterial processes in a small way along with massive water changes from tide changes to keep them healthy.:beer: :beer:
 

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Discussion Starter · #3 ·
I have a pretty good idea where that got started since I've only seen that on the hobby boards.

Reefs rely on sand and grass beds more as a import than a export.

If it was a export mechanism, imagine a closed loop where the water is flowing from the reef to the filter (sand/grass beds) and back again continuously. For one thing, there's no flow that way.

Sand and grass beds are major food producers for the reef, not filters.
 

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Ok, this doesn't perfectly fit, but...

#10 That somehow ripping up your entire tank and replacing the sandbed when it fails is less maintenance than siphoning the detrious regularly. (Which isn't much harder than a regular water change anyway.)
 

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Discussion Starter · #5 ·
LOL I was waiting on #10, but that's close!

There's even a easier way if you set it up right to begin with.
Keep in mind, since DSB's don't process phosphates you'll need something like a algae scrubber and water changes anyway.
 

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Spanky said:
...Keep in mind, since DSB's don't process phosphates you'll need something like a algae scrubber and water changes anyway.
macroalgae, but I digress :lol: Settling tank and siphon... :D

I have a tight grip on all this fish poop and I'm not letting go!

An interesting side bar, on the new 180, I hav enot introduced light yet, and notice a good bit of detritus (or possibly bacterial film growth on detritus) on top of the sand, but nothing in the sand except a few burrowing nematodes/annilids. it is mostlikely detritus from the live rock (about 300 lbs of cured Figi and Marshall Is rock) as the system ramps up, has only occasional feedings at this point and VERY strong skimming.

Comments?
 

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Discussion Starter · #7 ·
Tom,

That's exactly what it is. The rocks are 'cooking' as we call it and cleaning themselves up. As different things die off and different things replace them, they will get stable again. In the process they are creating a huge amount of detritus. They are also placing a huge demand on the system right now, so give them time.

I take a short cut and let them cook in vats where I can move them to new water and remove the detritus as fast as I can. Don't forget, just the nature of detritus contains nitrates and phosphates. I want that at as close to zero from the get go.
 

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yup, siphon party tonight at the Walnut Grove Seaquarium. Interesting thing about this, these were cooking for 4 weeks in kiddie tide pools in the carport, yet they are still shedding a large amount of detritus. I don't have macroalgae in the system yet and no light, so there isn't anything to soak up nitrates or phosphates. Can't detect any nitrogenous compds at this point (although there is a trace nitrate showing), interesting that there is still this much detritus generation, although it is an incomplete system in that there are few benthic critters and none of the usual janitoral crew in the system yet. Part of the rock is from an established system, the rest is all rock that has cured for 4 weeks (the bulk of 300 lbs).


...and YES, it does have a dsb IN the tank :D

although I am having many thoughts about the settling tank and refugium/macroalgal filter in the support room. I may go with an OPEN kalk top off system (open in the sense that it is an IO bucket with a small MJ PH to keep the stuff mixed, and another connected to a PH to do topoff directly into the sump where the returns come into the sump.

Still experimenting... this is the system that the remaining specimiens in Wellford will be transferred to.

In a related issue: The Wellford system (6+ YO 15cm Southdown DSB) has started some small cyano patches, the following I am sure have contributed to this:
  • decreased kalk supplementation
  • decreased feeding (counter intuitive, but related to the Foxface eating the remaining macroalgae in the display)
  • age of the SB (I may have reached the limits on this system)
  • Less time to do maintenance (the usual siphoning of the sump, etc
  • skimmer failure (pump finally gave up the ghost)

I will still be testing the deepest parts via cores for the nutrient levels in this system, but now I feel that there has been a break in the continuity of the conditions for this system, I'll prolly still use the sand to seed new tanks for a while, but for the most part, it will be a "wash and reuse" the stuff that does not dissolve or float out of the washings.

More later! The lights need finishing!
 

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That reefs rely on sand beds and grass beds for filtration.
If this were true, the lagoons would be cess pools and the reefs wouldn't be bothered so much by sedimentation and ag run-off from populated shoreline areas.

That DSB's are some how producing all this food for corals. (partly true but not the way people seem to think)
Bacteria being trapped by the coral's mucus?

#6 The ocean naturally protein skims.
OK, I was given the protein skimmer/foam on the edge of the beach ananolgy more than once when I was starting and asked "What does a protein skimmer do?" Is that what you're referring to?

Set me straight, Jerel ;)
 

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Ok #4 and #8 got me confused a little. are you saying for #4 it is just mega water changes keeping things clean and not the bacteria. i guess the way you have them worded it is confusing to me, they seem to be saying contradicting things.

G~
 

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Discussion Starter · #11 ·
Alice said:
If this were true, the lagoons would be cess pools and the reefs wouldn't be bothered so much by sedimentation and ag run-off from populated shoreline areas.
Good point. The obvious comparison is - take sand beds and grass beds out of the formula completely. You still have reefs, and there are plenty of examples of that all over the world. People that didn't know any better, noticed that sand/grass beds were adjacent to reefs and made a big assumption. Sand/grass beds are major exporters to the reef, not away from the reef. They are a major source of natural pollutants to reefs in the sense that they can export so many nutrients to the reef, unless that reef has enough flushing to keep it clean, you end up with exactly what you end up with in a high nutrient aquarium. Hair algae.

Alice said:
Bacteria being trapped by the coral's mucus?
Partly, but mostly feeding a steady stream of nutrients into the system to feed bacteria or just there for the taking to be absorbed directly.

Alice said:
OK, I was given the protein skimmer/foam on the edge of the beach ananolgy more than once when I was starting and asked "What does a protein skimmer do?" Is that what you're referring to?
And it's a dang good one. Only in a real skimmer, things are removed from the system. ;)
 

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Discussion Starter · #12 ·
#4 That reefs rely primarily on bacterial filtration.

Without the bacterial breakdown of various wastes and such, there would be no liquid nutrient soup. However, bacteria work at the same speed on a reef as they do at home - s---l---o---w---l---y. So even a reef can't rely on bacteria as it's primary filtration. A reef relies on flushing.

And no the critters on a reef work as slow too. Two things, you reach a point on a reef to where that's it, no more room for critters - just like at home. So even though there's a certain amount of nutrients locked up in critters, that number is static. So you still have a constant amount of waste that needs to be flushed.

#8 That natural reefs are not bacterial driven also.

I see where a lot of people have the idea that reefs are critter driven. That you can dump any amount of nutrients on a reef and the critter population will grow to consume it. See #4. The only thing capable of exponential growth that rapidly on a reef is bacteria in all it's forms. Next is plants (algae).
 

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Quote:
Sand/grass beds are major exporters to the reef, not away from the reef. They are a major source of natural pollutants to reefs in the sense that they can export so many nutrients to the reef, unless that reef has enough flushing to keep it clean, you end up with exactly what you end up with in a high nutrient aquarium. Hair algae.

Jerel,
Can we assume the same thing with mangroves?
 

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Discussion Starter · #15 ·
In a natural mangrove area, just like grass/sand beds, it really depends on where they are and flow directions. With mangrove areas you also have to be careful to not compare free standing with areas that receive a lot of runoff.
In both cases (mangrove and grass) they can be used to filter runoff before it gets to the reef.
In almost all cases though, you have mangrove surrounded by grass/sand or flush.
 

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Some funny misconceptions I've read about DSBs

I must say when I read this business about the exchange of nutrients and cleansing of water by seagrass beds and shoreline sediments, etc, I was skeptical.

I live in Queensland, Australia, and know a good deal about the Great Barrier Reef. Once you get away from the coast and begin to encounter reefs many miles (in some cases, hundreds of miles) from the coast, any suggestion of immediate relationship between those pristine reefs and coastal ecosystems is ludicrous.

I can well understand that a close in-shore reef may be affected by and in turn may affect shoreline environments. I can also understand an oceanic reef feeding a nearby seagrass meadow, and (depending on current) receiving from the meadow nutrients/organisms beneficial to the reef. But the massive currents (not just laminar) operating in these areas cause dispersion of nutrients very quickly, and not always necessarily in the directions one would expect.

In the big picture, these nutrient sinks obviously affect the sea as a whole entity - over long time periods - but ocean reefs could not be said to be interacting with coastal sediments in any sort of short-term meaningful way.

Les
 

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Discussion Starter · #19 ·
Hey Les, Welcome aboard!

Those offshore reefs of yours are a perfect example. All of our studies have shown that by and large sand/grass beds export to the reef, not the other way around. Without a good flushing out, the reefs that get too much aren't doing well at all.

Even with that, under certain conditions, nutrients are cycled from the reef to the grass/sand beds. That in turn is cycled back to the reef. But that's not the system that makes it work. When that happens, without flushing again, you have big problems with that reef.

Welcome again
Jerel
 

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Discussion Starter · #20 ·
Which brings me to #11

Never assume because it's a 'scientific' paper that's there one little bit of fact or truth to it. Even if it's peer reviewed.

I see a lot of that on the hobby boards. People throw around 'scientific' papers and links that they find on the internet to back up their opinions.

For example:
I could write a paper right now, not only showing that DSB's are impossible, aquariums are impossible, the moon is really made of green cheese, and Alice used to be called Richard.

Have it peer reviewed by the top scientists in the world and published within a week.
 
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