Can bare bottom have Refugium w/ DSB?

[reef_dude76]

Here is another stupid question of mine. I see all the time the comment that sand beds "crash" and release nutrients back into the system. Why is it that no one says that LR "crashes"?

Detritus gets trapped between sand grains and accumulates, detritus gets trapped in LR cracks and crevices and accululates. I have even heard people talk about LR "leeching" elements back out into the system. Would this be the equivelant of a LR "crash"? And if so, does this mean we should replace our live rock every 2-3 years to prevent the "crash"?

[barryhc]

Both sand and LR process Nitrate and "sink" Phosphate and other compounds and heavy metals, Plain and simple. Neither one "leaches" anything back into the water, it's just that when they become full, they can't hold anymore, and water column values rise as a result.

You can "cook" your live rock, and rejuvinate it to some degree because it has rather large openings to be cleaned out, whereas sand's pores seem to be too small to rejuvinate.

The biggest point to Bare Bottom methodology is to keep the detritus removed to avoid it's breakdown in the tank.

Exactly the same reasoning can be applied to DSB systems with much benefit.

The biggest differential between sand bed and bare bottom, from previous arguments came from avoiding skimming and high flow in some sand bed systems, and with their inclusion, the difference really "narrows" a lot.

The "VERSUS" really isn't necessary but the good husbandry of detritus management is a plus to all systems.

> Barry

[ONEMANBAND]

If running a BB system properly the rock will have little detrius in it (cooked) from the start, and having high flow/ powerful skimmer/ frequent waterchanges etc. will keep the detrius in ther skimmer cup vs. collecting in the system. To answer your question about why its sandbed leaching vs live rock leaching you need to consider the surface area of sand particles vs rocks. The sand has much more surface area to for bacterial growth, and to trap detrius. True- eventually the rock will collect detrius but not nearly as quick as the rock.

[MiddletonMark]

Exactly.

Some of the `sink' of LR IMO is combatted by the fact that it's normally elevated, with good flow going around/through it. [both substrate is not]
While it may hold detritus for a while - there is `somewhere to go' for debris - in substrate, there is nowhere that gravity can take stuff.

Most folks who go BB remark at how much their rock `sheds' the first month or two ... material coming off the rock. Without disturbing, does the same thing happen in the same quantity from substrate? IMO/IME ... no.

Part of BB's benefit, IMO, is that with a lessened bacterial biomass - nutrient issues can be affected through heavy export, w/c, etc etc ... where it can be a long road eliminating stored nutrients from both LR + substrate IMO.
Don't take this as an argument against bacteria, or for a `sterile' tank ... but one strong benefit to a DSB was always argued the absolutely massive surface area in all that sand for bacteria. This would, to me, be an attempt to maximize bacterial biomass in the tank; and I would just argue that maximizing that might be against what I try to accomplish with BB. Not to say we're combatting bacteria or the like - but rather, we're not trying to maximize it.

Does that mean anything in regards to Barry's last post? Not really - as he's talking about good husbandry IMO, something that would benefit any reef aquarium. I'm happy for my BB tank, partly because it has taught me to keep any aquarium better IMO.

[reef_dude76]

Reading the last several posts it just became very obvious to me that debating which is better, DSB vs. BB, is really a debate comparing apples to oranges. The actual point that is being debated is which "type" of system would benifit from having a sandbed, and which "type" of system would not.

What the advocates of bare bottom reefing are actually saying seems to be : if you are trying to keep corals that come from nitrient poor or starved portions of the reef ... i.e. ... sps corals, then don't use a sandbed because the added biomass of "bacteria" undermine your attempt to create a nutrient poor environment. Well ... of course ... why would you try to keep something in an environment that it doesn't like. That would be like trying to keep a lion in a 2' x 2' cage and debating that it is not thriving because of the composition of the ground it is sitting on, not the fact that it needs more space to roam.

Contrast that with certian species of LPS, polyps, and mushrooms that come from nurtient rich lagoon and inner reef areas. Here a sandbed would be of use to keep nutrient levels higher (this is of course a relative statement, you obviously are not going to strive for phosphate levels of 10 and promote hair algae or cyano growth) but again I am talking about trying to reproduce a specific niche in the reef ecosystem.

Which to me, therein lies the answer to the BB or DSB debate. First figure out what niche of the reef you are trying to keep, and build a system that approximates the conditions as closely as possible.

I apologize for the soap box, but am I off base with this line of thinking? I figure this is probably the best forum to ask as all you guys and gals in here are trying to keep the more difficult to keep corals and thus are well read and versed in reef husbandry.

[barryhc]

The bacteria "problem" just doesn't "wash". If it did, the BB boyz would be trying to find something to replace their live rock with, and they aren't.

Nutrient issues need to be dealt with thru limiting import and promoting export. The surface area for bacteria in a reef tank affects the tank's ability to process Nitrate primarily. That amount that is not initially removed via skimming, will be processed by both live rock and sand.

It isn't a difficult thing and there is no need to promote "mutual exclucivity". They work just fine together.

It is overfeeding, and negligence in detritus removal that cause problems in DSB's and exactly the same is true for BB.

The sand bed is not creating bio-load, it is processing it. If the flow and skimming are being handled well, the sand bed doesn't have that much work to do, and will last an extremely long time. Not forever, but 10 to 15 yrs. isn't bad.

> Barry

[MiddletonMark]

Actually, IME, all corals would benefit from pretty much the same conditions in this regard. The differences would be pretty minimal. [I'd check Chris Jury's article in Mar2006 Reefkeeping, I think he argues this well].

I think that once livestock are assured to do ok without substrate, it gets to `which system can you keep best?'. Everyone's different, and we see tanks from 10g to 250g+ displayed here, with different equipment, setups, etc etc. Is there a suprise different methods work better for certain folks?

[RichConley]

Originally posted by reef_dude76
Reading the last several posts it just became very obvious to me that debating which is better, DSB vs. BB, is really a debate comparing apples to oranges. The actual point that is being debated is which "type" of system would benifit from having a sandbed, and which "type" of system would not.

What the advocates of bare bottom reefing are actually saying seems to be : if you are trying to keep corals that come from nitrient poor or starved portions of the reef ... i.e. ... sps corals, then don't use a sandbed because the added biomass of "bacteria" undermine your attempt to create a nutrient poor environment. Well ... of course ... why would you try to keep something in an environment that it doesn't like. That would be like trying to keep a lion in a 2' x 2' cage and debating that it is not thriving because of the composition of the ground it is sitting on, not the fact that it needs more space to roam.

Now, the problem with that, is your are arguing that DSBs are bad for SPS, and I've seen enough old, beautiful DSB tanks to know thats not true.

As to what Mark said (I think it was him) "if rock was bad BB guys would be looking for something else" Why? If its not bad enough to cause a problem, thered be no reason. I was more talking about the fringe... IE if I get a big enough skimmer, could i run without LR. I think the BB guys were basically asking the same thing.. IF I get a big enough skimmer,and enough flow, can I run without sand. Obviously, yes.

The question is, can we take it 1 step further?

[ONEMANBAND]

The sand bed is not creating bio-load, it is processing it. If the flow and skimming are being handled well, the sand bed doesn't have that much work to do, and will last an extremely long time.....


How is a sandbed full of bacteria processing nitrogen not a bio-load on a system?

[MiddletonMark]

When power goes out, that sandbed bacteria is consuming precious oxygen and can cause a problem.

Explain to me how this is not bioload?

[Ewan]

I'm with Mark. A sandbed is a very large bioload. When I removed my sandbed, I was amazed that I had to throttle back my calcium reactor, The difference in calcification was amazing.

Also, I found that my pH swings became much smaller once I removed the sandbed.

[barryhc]

Originally posted by MiddletonMark
Actually, IME, all corals would benefit from pretty much the same conditions in this regard. The differences would be pretty minimal. [I'd check Chris Jury's article in Mar2006 Reefkeeping, I think he argues this well].

Really nice article By Chris. It's the different types of food, flow in some cases, and light of course that makes it quite difficult to spread "diversity" all the way to "the borders". This is our excuse ( at least ) for more tanks. It is the food though > type, quantity and method of delivery, and then most especially "clean-up" that "muddies the waters".

I think that once livestock are assured to do ok without substrate, it gets to `which system can you keep best?'. Everyone's different, and we see tanks from 10g to 250g+ displayed here, with different equipment, setups, etc etc. Is there a suprise different methods work better for certain folks?

There are quite a number of animals that need the sand to survive and prosper. For those who are not interested in these animals, Bare Bottom becomes a valid option.

You're quite right Mark, the Aquarist is an important consideration in the make up of the system, in many ways.

The Question OMB, is, How is a sandbed full of bacteria processing nitrogen, a load on the system?

> Barry

[RichConley]

Originally posted by MiddletonMark
When power goes out, that sandbed bacteria is consuming precious oxygen and can cause a problem.

Explain to me how this is not bioload?

We had a 125 gallon with 6" sand bed (roughly 5 years old) lose power for 8 hours a little while ago. The temperature in the tank dropped into the high 60s. (gotta love new england). She lost nothing.

All that was running was a $10 battery powered air pump. If that can keep that tank alive, then I dont think its enough of a consideration to worry about.

[reef_dude76]

MiddletonMark and barryhc: I think you made very profound statements with those last posts. It IS about which system you keep best, or rather which system you will bother to maintain. And weather or not you pay attention to what you are putting in and pulling out of the system.

I'm not sure what you mean by "promoting mutual exclucivity" though.

My whole point, which both of you made and thank you for doing so, is not to run anyone who wants to keep BB or DSB into the ground for doing so. But to point out that the majority of the time I have seen BB promoted because it is "eaiser" to remove waste. Well, yes and no depending on what you are trying to remove and how are you trying to remove it. It will help to remove detritus but not dissolved organics (you still need the skimmer for that).

Likewise, will a DSB last forever? No, of course not. The question is do you like the look of sand enough to fool with replacing it in 2 - 10 years depending on how well you manage import and export of nutrients for the system as a whole.

I guess what gets my dander up is broad comments about things like bacterial biomass and BB is better than DSB or vise versa beacuse of x, y, or z reason when most of the time, IMHO, lack of sucess with a reef tank is do to:

1. Poor planning
2. Buying cheap equipment that doesn't work
3. Not doing your homework before setting up the tank either regarding system design or health requirements of the organisms in the system.
4. Being lazy and not doing your routine maintence
5. Not paying attention to what you are putting in the system

Here is my main motivation. I tried to keep sps in the past. I failed .... horribly. Why? I didn't know. So I came to RC and asked. I was decimated for keeping a DSB, and this was labeled as the reason for my failure. I took the DSB out. I still couldn't keep sps. Why? I didn't know, so I asked again. This time I was told it was due to my subpar skimmer a (CPR SR4). By this time, I was moving so I tore the reef down, moved, and spent 3 months trying to figure out my mistake. Which I concluded was poor system design in both plumbing, skimmimg, and circulation as well as my being lazy in routine maintence. I replumbed the tank, changed the postion and plumbing of the same skimmer, added a HOB refugium to reduced the amount of detritus that could settle, put the DSB back in, and went with it. Four months after setup, sps are growing (still working on coloration) PO4 is zero, nitrate is zero, water is crystal clear. Thus it wasn't my DSB, it was me and my lack of having a clue about what I was trying to do.

[ONEMANBAND]

Barry the bacteria are alive and growing , this growth is by converting Nitrogen and Phosphates
here is a good article that is pretty good reading for anybody running a DSB.
http://www.reef-aquarium.net/resourc...trate/dsb.html

[ONEMANBAND]

It should not be a Pro/Anti DSB or BB argument, the origional poster was inquiring about running a DSB fuge on a BB tank, and thats the question. . This goes against the premise of the BB method. So my answer is still NO. Does anybody see a plus side to adding the DSB fuge? If you run a DSB you should know that it is a living thing.

[barryhc]

Thanks "Dude".

"OMB", the bacteria aren't doing much with the Phosphates. The phosphates are mostly "sinking" into the bed. You really need to understand the functioning of a sand bed better before you can address the question. Here is where you can get some excellent information on DSB:

http://archive.reefcentral.com/forum...hreadid=745968

I can't deal with Shimek's reccomendations. He is too rigid to understand his own observations, and beyond that he is just plain "fuzzy".

Who's starting an argument, I stated that they can operate together. They do not need to be mutually exclusive. I don't have a side.

The "premise" of BB, is to not put a bunch of gunk in a sand bed, and further, to use high flow with heavy skimming to remove most detritus before it can break down, and other organics and compounds, before they can build up. It works pretty well, but not perfectly, ask Mark. Finish up with water changes.

These are sound objectives. A remote DSB run properly, is not contrary to that premise.

The DSB in the fuge will keep Nitrates down. It will also reduce phophstes by "sinking" them.

> Barry

[icliao]

Since I live in Indonesia I have the luxury for low setup cost and I have done much experiment except pure bare bottom tank. I didn't liked the look then (and still prefer sand but ready to make the sacrifice.)

I have the following input purely based on my experience.

1. It is not difficult to keep coral alive and healthy regardless DSB, SSB or BB (supposingly) as long as other equipments are proper (skimmer, circulation and lamp and etc)

2. Live rock can become clogged. I had a nasty Bryopsis problem and after I replaced all my live rocks in my DSB system it never came back. (Already 8 months passed) I thought it is caused by my DSB initially.

3. So far I found DSB working fine and my 500GL has been up and running with DSB and refugium for over 3 years with amazing growth. The problem is I still get some nutrient and the color of my acroporas are still not maximum (it has improved) despite various efforts I made. (Additional good skimmer, additional circulation, upgraded lighting, coral feeding.)

I set up a 200GL tank for experiment purpose 5 months ago. In this tank I used SSB + DSB refugium. The nutrient is low phosphate 0.05ppm and Nitrate =1ppm with LaMotte tests but not 0 because I still have quick diatom growth. The color of the acropora is fine but not as bright as I initially bought.

My goal is not need to clean the glass so often but also very interested to see what happens if I remove all sand and refugium altogether.

[aurorafish]

This topic is beaten to death on this website. If its a BB display with a remote DSB then thats what it is!!!. Will it reduce nitrates? most likely since it will provide an anaerobic area for the nitrogen cycle to take place and Nitrogen gas will escape the system. Will it reduce phosphates? Seems to be a hot topic with many armchair quarterbacks and little scientific proof of the mechanisms occuring, the N cycle is pretty well know, the PO4 cycle is in a saltwater solution is subject of much debate among scientists/ experts as it is a highly reactive molecule and can follow many "paths" Does either substrate/lack of substrate make the corals grow without growing excess micro-algae? Thats up to the husbandry skills of the reefkeeper. Did I miss any beat to death DSB vs BB arguments?

[icliao]

I personally feel Nitrate and Phosphate can be easily reduce to a level where SPS can trive regardless DSB, SSB or BB such as below 5 ppm NO3 and 0.1 ppm of PO4 or below.

The main difficulty is to get optimal color of acropora. Sometimes even if the nutrient is undetectable but we can still see diatom and other algae growth to prove the nutrients are there.

Such as my 200GL only 1 ppm NO3 and undetectable PO4 (using Phosban and Rowaphos) and still I am not getting maximum color out of the corals.

[barryhc]

Originally posted by icliao
I personally feel Nitrate and Phosphate can be easily reduce to a level where SPS can trive regardless DSB, SSB or BB such as below 5 ppm NO3 and 0.1 ppm of PO4 or below.

The Phosphate value should be reduced considerably for some sps species, to <.03ppm. There are other considerations as well.

I think you should go ahead and try the Bare Bottom set-up and find out how it does. The system, including the refugium, will have to work harder if you remove the sand bed.

You might want to get ready to add another skimmer ( maybe you have an old one sitting around ) especially if you decide to remove the refugium. You could also add Chaeto to the refugium if you keep it running and that would help a lot if you don't already have it. Cheap 2700K flourescent bulbs from the hardware store if you go that route.

I think if it was my system, I would go BB first, and keep the refugium. Run the system for at least a year to get a clear reading of it's functionality. Then remove the refugium as well, if the results aren't yet satisfactory.

Remember of course, that there is more to it than just "sand bed and refugium", or not.

Happy Reef Keeping ! > Barry

[scott_richards]

Sigh...and the wars start again.

When will it end!?

Make a new forum for bb and a new forum for dsb already!

[icliao]

Originally posted by barryhc
The Phosphate value should be reduced considerably for some sps species, to <.03ppm. There are other considerations as well.

My 200GL has less than 0.01 ppm of PO4 and 1 ppm of Nitrate, does that meant nutrient not a cause for my some of my acropora not getting maximum color?

[MiddletonMark]

I too would agree with Barry - mainly just because it's a LOT easier to remove the substrate than re-establish the 'fuge if you decide going BB on the fuge wasn't what you wanted.

I think you might struggle more with the BB [with fuge as is] - I guess you'll be the tester there - but IMO it's a lot easier to remove that later vs. the time it takes to have a mature 'fuge like you do now. Once you remove that - you can't get it back - and so I'd suggest running with it as-is for a good while, see how things settle. If you still have problems 6-9 months later, then remove it.

I'd give it 4-6 months as BB before doing much though - I found after 3 or 4 months my BB really turned a corner - it seems like the tank + user get better in sync after 6 months, and it might take that long to get it starting to `work right' IME.

To me, also - having part of the system stable through the display tank conversion isn't a bad thing. Given your tank is stocked, a little extra stability probably won't hurt ... and 9 months later, when the 'fuge would be [or not] revamped, the display will be the stable part

[barryhc]

Originally posted by icliao
My 200GL has less than 0.01 ppm of PO4 and 1 ppm of Nitrate, does that meant nutrient not a cause for my some of my acropora not getting maximum color?

You had previously given values of .1ppm and .05ppm and then .01ppm for Phosphate, I'm just curious if there is a decimal point error anywhere ?

If not, then you are certainly in good shape with these numbers. There are organics that can't be read reasonably with standard test kits, as well as "cycling quantities", according to some, but that is beyond my current level of expertise to explain any better than that. Keep up the research, always !

Water changibg is a big factor in all systems. There isn't a magic number for it. It depends on "everything" ! You, the animals, the amount of testing, and feeding, all conspire to make water changing regimes highly variable.

Less water changing = more water testing, and more dosing.

Sand beds can actually help with this problem, by "sinking" many excess compounds, but they can't just sink forever without a means of export now can they? This depends as well on how selective you are with your foods.

> Barry

ooPS: Also, like Mark said, I think all systems need at least that 6 to 9 mos. for things to find an equilibrium. After that you can modify what equilibrium. Several thousand ways unfortunately, or fortunately, if you like !