BB vs. DSB

[Blade_Runner]

I'm been going back and forth on this too. With my 300 I'm splitting the difference. I put about 80lbs of sand in the tank as I simply like the look of a little sand. It's just enough to cover the bottom. I then put about 130lbs in 1 chamber of my sump to create a 2.5" bed.

IMO, it gives me the look I like. The ease of maintainance in the tank I want, and the security of a moderately deep and easily serviced sand bed in my sump.

[Covey]

Hey Inwall do you have any links to the "Sandbed as a nutrient sink" type links I would enjoy some more reading.

Those 4 maxijet 1200 were on a 75G with a wave timer. I have seen one guy with a 150 that had 3 SEIO 1100 that did little more than keep detritus out of his rock. Oddly enough he stop using them all. It was working to keep detritus out of the rock but it was just as good at keeping the fish out of the rocks too and they were not happy.

[RAVEN]

All this information and discussion is very interesting and informative but no where in this discussion about phoshates and nitrates do I see any mention about the role of macro algae and refugiums. I had a big problem with nitrates and phosphates in my reef tank until I added a refuge with a large amount of various types of macro algae that I harvest regulary. This has lowered my nitrates and phosphates dramatically and cut down on nuisance algae.
Karma for everyone for this stimulating topic.

[inwall75]

OK WOW!!!

I saw that Covey started a great topic that truly SHOULD be discussed. Luckily, 3reef can have discussions that don't turn into "my dad can beat up your dad" like often happens on one particular forum.

I have lots of documents that discuss nutrient sinking in sediments. However, the computer that had my links organized by subject matter died so it's going to take me a lot of work. Give me a little time. It is important to recognize that what is considered to be sediment by a bacterium is not what we would consider a sediment. A sand bed is a sediment, LR is a sediment, CaCO3 skeletons inside your SPS is a sediment.

Raven
This thread is likely to get extremely complicated because sandbeds don't work the way that Dr. Ron has sold it to the hobby. If you want to discuss refugiums, I would recommend starting a separate thread on that topic and then posting a link to it in this thread. Here's why. A sandbed and a refugium both handle phosphates and nitrates. However, they handle them in totally different ways. A sandbed is a long-term sponge that is left in the tank and a refugium is short-term sponge that is exported regularly.

To make sure everyone is on the same page, here are some cycles that we will be discussing.

[RAVEN]

I just threw in the blurb about refugiums because they play a role in removing nitrates and phosphates and feel they play an active role in addition to sand beds and wanted to create futher thought and discussion, LOL.

[inwall75]

Originally Posted by RAVEN

I just threw in the blurb about refugiums because they play a role in removing nitrates and phosphates and feel they play an active role in addition to sand beds and wanted to create futher thought and discussion, LOL.

Seriously, I think that a thread SHOULD be started on this issue. I would encourage it.

It's just hard to keep things straightforward on two different subjects on the same thread. Two threads helps keep things focused.

[inwall75]

I'm still grabbing links on this issue. In the meantime, I thought this would give people food for thought.

A healthy reef where most SPS are located is oligotrophic. Without getting too technical, what that means is "nutrient-deficient". Coral reefs are pretty much the most productive systems on earth. Confused??? You should be. How is the entire most productive system also nutrient-limited? It's real easy. It doesn't work EVEN REMOTELY like our closed systems. Is there nitrification and denitrification going on??? Sure....bacteria is everywhere. However, a natural reef operates more like a BB tank. Food comes in, a lot of it is processed by the reef, then even more than was imported is exported. I.e. tides sweep it out to the abyssal plains. That is how one of the most productive system in the world can also be nutrient-limited.

I keep corals that live in lagoons. Should I care about this thread?

Yes. While most softies can tolerate (and most actually prefer) higher nutrients, many are operating their tanks based on some falsehoods spread by Dr. Ron. Here's what Dr. Ron suggests. You should have an entire ecosystem in your tank. Bug 1 eats detritus and then poops out a smaller amount of waste. Worm 1 eats this poop and poops out smaller poop. This allows a different bug (bug 2) to eat and then poop a smaller amount. A different species of worm (worm 2) will eat that and poop yet a smaller amount. Eventually, it gets small enough that bacteria can eat it. Once bacteria take over, it continues to get smaller. Apparently, there is some type of bacteria that is so small that their poop is so small that matter can literally go poof and disappear. The thought that this can happen is against soooo many laws of nature that it is scary. Here's a very basic definition of the law of conservation of matter.

The law of conservation of mass/matter states that the mass of a system of substances is constant, regardless of the processes acting inside the system. An equivalent statement is that matter changes form, but cannot be created or destroyed. This implies that for any chemical process in a closed system, the mass of the reactants must equal the mass of the products.

Basically what that means that what you add to the tank, stays in the tank unless you export it. The real workers in your tank are bacteria and the worms and bugs merely provide bioturbation. Here's a test for single people (i.e. don't try this unless your spouse is out of town). Buy a shrimp from the grocery store. Take a glass of water from your tank and drop that shrimp in there. Bacteria will dissolve it to practically nothing in several days but it will stink to the high heavens. Then all of that matter that seemed to disappear will reappear as a dusting of detritus. Once the food source dies, the once invisible bacteria will start dieing off. The accumulation of their shells will slowly fill the bottom of the glass. The water will be cloudy because bacteria are cannibals and they will eat dead bacteria. The cloudiness is called a bacterial bloom. The mass of the shrimp is still in that glass. It is just broken down in and inside the bodies of billions and billions (maybe trillions) of bacteria.

Dr. Ron also led people to believe that the sand near coral reefs and seagrass beds filtered the products produced by the reefs. This again is incorrect. In nature they do exactly what they do in our tanks, they are a source of nutrient imports to the reef. However, there is one big difference. Sandbeds in nature don't just sit there for years upon years collecting detritus. Storms and tides remove the sand and detritus and send it to the abyssal plains. Then storms and tides send the sand back. It is pretty much a [CTRL][ALT][DEL] of the entire system. Here's how Dana Riddle (yes THE Dana Riddle) wrote about a recent storm.

Aloha,
We can't reasonably simulate a storm (this coming from someone living 150 feet away from a Hawaiian coral reef). Winter is the time for storms on this side of the island. I just recovered the pieces of my data logger instrument housing from an area sheltered from winter swells. This housing weighed almost 100 pounds before it (and its concrete anchor - epoxied to rock 4 feet above the tide line) was ripped up and deposited almost 10 feet above and far away from its original position. Rocks weighing 100's of pounds were also swept away. This lagoon had sand in it before the storm - but no more. But the corals made it through just fine (expect for those washtub sized colonies that were ripped off the bottom). Just wonder how many powerheads it would take to do that?
Dana

Here's what Dr. Ron said about the subject in 2003

The absolute position of the sediments will often vary from season to season, particularly in intertidal and shallow subtidal areas. Tourists who always visit a given resort at a particular time of year are often quite amazed when they return to the resort six months out of sync with their usual pattern and find the sandy beach they expect to see has vanished, leaving a hard coral pavement instead. Movement of sediments is less in deeper waters but it still occurs. In fact, one major characteristic of natural sand beds is their mobility.

http://www.reefkeeping.com/issues/20...ture/index.php

[inwall75]

BTW....Dr. Ron didn't invent the thought of trying to create an entire ecosystem in a closed system. He copied it from Walter Adey who is the inventor of refugia and Algal Turf Scrubbers with dump buckets. Unfortunately, his system failed at the Smithsonian Aquarium, The Great Barrier Reef Aquarium, and one or two more including the latest disaster, the Biosphere II. Here's a link to Matt's visit to the biosphere. A Trip to the Ocean @ Biosphere2

BTW, he's still employed by the Smithsonian but they put him in their Botany department. They don't have him doing work on large marine mammals anymore nor his research on mesocosms (enclosed ecosystems).

[Covey]

Originally Posted by inwall75

Once bacteria take over, it continues to get smaller. Apparently, there is some type of bacteria that is so small that their poop is so small that matter can literally go poof and disappear. The thought that this can happen is against soooo many laws of nature that it is scary.

I was under the impression that the last "poop" in the chain was the bubble of nitrogen bubbling out of the system. There doesn't seem to be any magic involved as the system seem to be working the how the Nitrogen cycle is suppose to. Your "closed system" are open in a way in that we allow gases to escape from them. There is no major violation the the law of conservation.

[Covey]

To the best of my knowledge Lee Chin Eng was even earlier than Adey. I am going to see if I can get Dr. Ron opinion. Unless RC has got him in some sort of contract