DSB and cukes

[Dmitry]

So, do you guys here recommend a DSB or not? I don't want a bare-bottom and just see quite bit of conflicting information on the benefits and risks of DSB, which everyone downplaying the risks of both. Just wondering what ya'll think!

Also, cucumbers - I'm sure it'd be beneficial to have one, though supposedly keeping one also could be risky. (And they're just nasty looking. If someone could come over when the new tank is set up and drop one in so I don't have to deal with it...it'd be great!)

 

[House of Laughter]

Dmitry,

There is much literature out there about the DSB, Jalabert,, and Berlin Methods Jalabert is a plenum and Berlin, well , is skimming.

I, over the years have used all 3 and my tanks have thrived.

DSB have serious benefits with equally as serious a risk - bottom line, this hobby is not like a gerbil you can put into a cage with food and water and never look at it for months - it just doesn't work out that way. that being said, you chose your method by what you want to spend you time on (at least I do).

If you want to go DSB, then you'll spend your time testing for nitrates and doing water changes. If you want to do a plenum, then you have to do water changes and keep your eye on it szo it doesn't leech into your water column, and if you want to do a DSB , you have to test for other things and make sure you invest in critters so they turn the bed enought so that is doesn't go south with detrius. The Berlin (skimming) method is also missing things I believe since you can't rely on a skimmer alone to balance your tank.

Anyway, this time around I did a shallow sand bed in my display tank and did a deep sand bed in my fuge because if the DSB goes bad, I can rip it out and replace it whenever I want - and the shallow sand bed in the main display is easily turned over by the appropriate janitors.

I also oversized the skimmer for the tank, which I recommend no matter how you decide to do the substrate.

anyway, I'm babbling.

House

 

[Dmitry]

Actually you've given me a very good suggestion: shallow bed for the tank and DSB for the sump. But...who turns over the sand in your sump?? Do you just dump a bunch of snails and hermits in there? What will they feed on? I also figure that even without a sand-sifting crew in there one can stir the sand in there by hand (or a stick.) It's a significantly smaller area to cover with no real obstacles. This way we can ensure ourselves that that it was always being well stirred.

I really don't want to deal with a plenum!

 

[ShaunW]

Once you set up a DSB you MUST NOT disturb it! Just leave it alone to do its business. The benefits of a DSB are setting up the different bacterial environment, i.e. microaerophilic and anaerobic, nessesary to break down nitrate to nitrogen gas (the final step of the nitrogen cycle).

Small critters will take care of the nessesary "top soil" moment. If you break the anaerobic layer manually you will crash the DSB, because oxygen is toxic to anaerobic bacteria.

 

[Dmitry]

So then what are the risks of the DSB if it's not the possible trapped gasses due to lack of sifting??

 

[House of Laughter]

As Solbby mentioned, CRASH - it will kill everythig in your tank in a day or so,

That being said, never stir your sand bed, leave that to the animals that do it naturally, and I don't recommend putting it into a sump. but in the refugium.

I have read this book by Ron Shimek and recommend reading this and starting there - it gives great explanations of what it is, does etc.

http://www.rshimek.com/reef/sediment.htm

Enjoy, it is just one of the articles from the book

House

 

[Dmitry]

I've read that article before and the author dismisses the idea that the gases will be formed in such high concentration at the bottom of a DSB that they can actually do any harm. He says the smell is stronger and even if you can smell it, it won't be strong enough to cause harm. The only draw-back he seems to have is that there's not enough life in the sand to sustain everybody that eats it for very long. So...according to that article there really are no risks to having a DSB! While many others argue that there are - they must have a reason for saying that. Why will it wipe out the tank in a day or two if it goes bad? And then presumably...unless the DSB is disturbed - and in a fuge it shouldn't be - there are no risks. Right??

 

[ShaunW]

So then what are the risks of the DSB if it's not the possible trapped gasses due to lack of sifting??

The problem that occurs with a DSB over a considerable period of time (many years) is that it starts to leak nitrate and phosphate back into the water column. This happens because it is no longer working as it should be.

What a DSB does is sets up different bacterial niches (anaerobic) that works to break down nitrate and phosphate, i.e. stratafied layers of bacteria. At the boundary where oxygen is available the anaerobic and aerobic bacteria compete for nutrients (other than nitrate), to the point that the aerobic bacteria win out due to their location at the upper layer of the DSB. But to account for this the anaerobic bacteria spread out to completely seed the entire microaerophilic region of the DSB. But since the DSB is limited in size and space their ability to spread is limited. Therefore, to continue to grow and acquire the nessesary nutrients to survive, the anaerobic bacteria, over time, push into the upper oxygenated layer but as they do they encounter oxygen which is toxic to them. So they are dying off and it is this bacterial die off that acts to release back into the water column nitrate and phosphate. In nature the sand bed extends down many feet so if you had a deep deep sand bed such an occurance would not occur. Also the abyss in the ocean acts as a huge remote source of constant water and as a nutrient sink.

 

[Dmitry]

So then really...a DSB is guaranteed to crash at some point down the road?? Unless one plans to change or completely overhaul their tank every few years (which I guess we all do when we upgrade!), why would anyone set up a DSB knowing that in a few years their tank will be wiped out?! It sounds like HOL's solution of a shallow bed in the tank and a DSB in the fuge is the ideal solution, where the DSB can be replaced every few years without the hassle of emptying out the tank!

I picked up the sand today from a guy who was giving it away for free at Reef Central. I was a bit disappointed because it wasn't clean! (Which is why he was getting rid of it and going bare bottom.) It is definitely live becasue I see stuff crawling (and he gave me a bunch of snails), but I wonder if it's worth keeping. Perhaps for the fuge where appearance really won't matter... Now one big question is how best to store it for a few weeks until the tank is set up? I've got it in a 5 gallon bucket and it's about half-way full with sand. Should I stick an air-head on the bottom? Or just leave it as is in and simply make sure I keep up with evaporation? It's a very very DSB in the bucket!)

 

[House of Laughter]

Dmitry,

I think the final sloution you look for will eventually be defined by what you want to do in the future - I am going with the DSB in fuge, becuase this is the final tank I will ever have (in this house

If you may eventually upgrade, then why worry about it ? I would say, though, if you go DSB, try to have 5-6 inches so that you try and prolong the "crash"

In the bucket, I would put a heater and an airstone or very small powerhead.

Hope that helps,

House