what's the problem with DSB?

[bonny]

well while researching this new tank i have always been told to set up a DSB now i have read things in the think tank that make me think otherwise. Should i not set one up? surely these things are beneficail because of the nitrate removal?

[MontanaRocknReefer]

Have you read this thread? Interesting discussion on DSB! http://www.thereeftank.com/forums/sh...threadid=20279

[Doug1]

Honestly, this is becoming a hotly debated topic, but my take is that any system wherther its a DSB, Plenum, Algae filter, or whatever, all have certain limitations in the typical home aquarium.
Most stem from the fact that we are dealing with small closed systems that by virtue of bioload, overzelous feeding, sloppy husbandry and simply not knowing the dynamics of a given system tend to overload with detritous over time. Most reef tanks have nowhere near the bio diversity found on a wild reef, nor the dilution factor of the open ocean, or large areas of close proximaty environs that are more suited to utilizing waterborne nutrients, like mangove swamps, turtle grass sand beds or other biotopes that are often found in conjunction with reef areas .
The gist I get from the discussions is that without gross detrital removal a deep sand bed will eventually reach a point of saturation. Another factor that I see is trying to keep up adequate numbers and varieties of all the critters that form the various levels of the food web that process wastes.
Not a simple answer, but its not a simple question, then again I may be way off base as this is just my take on what I have read. HTH
Hopefully someone with a better MB education can correct or elaborate to help you out

[bonny]

yeah i have read part of it, that is what got me wondering however i can't seem to find anywhere what exactly is the problem with them? I know people on other forums who have had theirs set up for years and still swear by them.

[bonny]

doug you beat me to the post. thanx for that so if i was to do light gravel vacs every time i did a water change, just enough to remove the surface detrius this should help with the longevity of the DSB

[Doug1]

Well detrital removal would help I think, at least thats the thinking. The other issues tho as I stated are adequate populations on meofauna, infauna, detrivore, grazers, etc. to help with what you dont get during cleaning phases. Also the question of how much to clean at a time rears its head. My thinking is that vacuuming will invariably remove some of the beneficial benthic organisms we want and need. A tricky balance and as I stated earlier, a debated one
What I have gotten from the discussions seems to point to a few options, I will try to outline
A: Let DSB develop and replace after x number of years when problems beome insurmountable with present methodology for dealing with
B: Thin sand layer vacuumed frequently in sections and supplemented as needed
C: thinner layer of larger grained substrate, typical of live sand sold in the trade, again vacuuming parts in rotation, combined with very high internal water flows suspending much of the waste matter, relying on heavy skimming and mechanical or bio-filtration in a remote area that can be isolated and redone as needed.
D: A large system with lots of biodiversity that has the availability of frequent flushings with SW either all the time or part time. The solution to pollution being dilution.
I wont address plenums as thats an area I way too confused to try
Again, my take on the whole thing is to research and choose after one feels comfortable they have at least a basic idea of the processes involved in the method of choice. In the 5 years I have been into reefs I have learned to never stop learning. Most of these methods will work to varying degrees, the more you know the better your chances , but I have seen too many nice tanks with a few years on them that have had minimal attention to discount luck and groovy karma. I know thats not scientific but I cant argue success.

[bonny]

ok *confused*! well i think i will set on the stand 4" markers and everytime i do a water change (i have been told once a month once the DSB kicks in) i will vac that area and then mark it on the stand so i know not to do that side again. This should give time for the DSB to recover.

[cyberchef]

If your going to vaccumm the S everytime you do a water change then I would not go deper than 1 1/2" - 2". Doing a DSB of 4" will allow a anaerobic as well as a anoxic zone to form and vacumming it will upset the balance of the zones and could have potential to cause havoc with the whole tank.

Personally I like plenum systems even tho I know and understand the downsides of both it and a DSB. I really don't like the look of a bare bottom tank so for me that's completely out of the question. No matter what you decide to do, good husbandry and common sense will go a long way to allowing it to last a long time.

[bonny]

well i need a few things explaining here. What's a plenum and what exactly do you mean by good husbandary?

[Patman]

When I started people said have an empty bottom....then the DSB craze came up...which I have been using for 4 years.....now its the "the sky is falling" attitude towards DSB....and in 5 years people will say, "you should use a DSB". It's the nature of the hobby.

I'll use DSB because the work for me...when the day comes when they don't, I'll stop...


Pat

[bonny]

thanx very much well i like i said i have known people have them on their tanks for many years and they are really impressive. Thanx for the input everyone.

[Doug1]

Husbandry would be the sum total of actions required to try and provide the best environment possible(within reason) for the particular animals you choose to keep.
Factors to consider would be choosing compatable animals, knowing their particular needs, as in lighting, feeding, water flow and tolerance to elevated nitrate/phosphate , considering the effects of organism produced chemical or biomechanical defense mechanisms, calcium needs, and the overall process of feeding enough and ridding the closed system of unwanted waste products, whether is solids such as fish feces, coral mucus, and uneaten food stuffs.
Adequate water changes and chemical additions if needed( another controversial topic, deserving its own discussion)

[bonny]

ok thanx very much. I think i have learnt as much today as i have over the past month of research. First thing i am doing when i get back from holiday is getting some marine books out of the libary, then getting a job at the LFS so i can pay for the **** thing

[cyberchef]

Thanks Doug, good explanation..

A plenum is a space, under the DSB, created using PVC pipe and/or eggcrate (covered in screening so as not to let sand fall through) that forms a anoxic zone to process nitrates. This space, if set up properly, should be completely devoid of oxygen.

Pics of the plenum I made/use can be sen here...

http://www.thereeftank.com/forums/sh...&threadid=6655

[blumoon]

I just spent all day removing the DSB from my 135 and put it all in my 100 gallon refugium.It was like a sewer, i'm running carbon now.The refugium has Bristleworms,pods,myris shrimp and algea.I like this way alot better the main tank looks alot cleaner plus the fish were eating all the worms and stuff and i couldn't keep enough critters in there to keep the sand bed clean.Right now it's bare bottom i might put a thin layer of crushed coral on the bottom since it can be vacuumed but i'm not sure yet.I mainly have sps corals,also have a Rose Anemone.
Bill