How Deep Is Your Sandbed?

Karla,

Thank you for the encouragement, and yes I am back on the job and doing things a bit differently this time.

MR,

What caused the crash?

Well here's a thumbnail sketch with some 20/20 hindsight. Tank started in May 2002

Novemeber  2002
Tank was going really well, 6inch DSB, no problems, just really healthy, fish happy, getting more coral, even had a small clam as a gift from a friend.

December  2002

Started to see a lot of brownish algae but was assured this was just a normal part of the cycle amd it would pass, fish still happy, coral still happy, clam happy

I must admit that at this stage I was always planning to remove my DSB, and at another time I will explain why if you are interested in my reasons.

End December, early January.

Hooray, holiday time in Australia.

Tank is still looking OK, but brown algae is growing so I reduce photo period and this starts to help a bit.  Everything still looks happy, but a strange smell develops  :-/

Mid January while out.  Chromis decides to do the leap of faith, goes into the weir and down the drain pipe and becomes stuck half way down and reduces the flow dramatically.  Tank sloooowly fills and overflows, water runs down a powercord and completely fuses the powerpoint.  No electricity to the tank.  

Come home and phew the smell, but fish are still alive, coral looks sad and clam is dead ( empty shell ).  So I ran some extension leads to other power points to get the circulation going and keep alive what I could.

Next day all dead and tank stinks like a sewer

Removed all the dead animals and coral and even the rock.  The top of the sand was jus covered in worms and some were huge, if I said there were 1000 it would not be an exaggeration.

Drained the water and it smelled foul, removed the sand bed and it smelled like a mixture of rotten eggs and boiled cabbage.  I was proud, only vomitted twice  

I know this doesn't actually answer your question MR, but the best I can do is describe the events.

John

 

Nope! That answered my question! Nasty!

That rotten egg smell was a good thing. It is called anerobic bacteria! It is what helps convert Nitrates into gases.

So the DSB was working.

Anerobic (not sure if that is spelled correctly) is where there is no oxygen. You get that a lot in ponds or lakes that are not aerated properly!

 

JohnO, sorry to hear about your crash.  I had one of those sand-bed crashes several years ago.  Very frustrating, very disgusting, made me want to give up the hobby, and I did, for over a year. :-[  I'm glad to hear that you aren't giving up.  The benefits of the hobby far outweigh the setbacks.  And, maybe you don't want to hear this right now, but we learn so much about ourselves in a crash like that.

As my signature says, I have a 4" DSB. That is, of course, an average, taken across the tank. I started out with a slope, but over the passage of time, sand seeks to be level. There are waves and such in it now, mostly caused by fish and rocks being moved. But, all in all the sand (I use aragonite sand) is still fairly level.

I also have a 4" DSB in my sump/refugium.  I used a mixture of half aragonite sand, and half Kent Marine Biosediment.  The Biosediment is just TOO FINE to be used alone (IMO), but with the aragonite sand it works well.  It anchors my caulerpa, and live rock; and performs the function of a DSB just like the one in my main tank.

I'm going to attach a picture of my sump/refugium.  I'm sure it will start several discussions.  ;D

Edit: I am interested in grain size. Do most of you have the play sand with the 1mm grain size sand? Or do most of you have the aragonite sand with the 2-3mm grain size sand. Mine is the latter, and I believe it is better than the 1mm grain size which becomes too packed to be practical. I'd like to hear some opinions on this issue, as well.

 

[quote author=MacnReef link=board=Sand;num=1042524307;start=0#11 date=03/12/03 at 05:38:11]
That rotten egg smell was a good thing.  It is called anerobic bacteria!  It is what helps convert Nitrates into gases.

So the DSB was working.

Anerobic (not sure if that is spelled correctly) is where there is no oxygen.  You get that a lot in ponds or lakes that are not aerated properly![/quote]

mR,

Without wanting to be too picky, the rotten egg smell is hydrogen sulfide which is the biological result of the bacteria doing it's job. All well and good, but keep in mind a major infauna disturbance (or by the aquarist) to hydrogen sulfide somewhere in the bed, is a quick way to end all life in the system! So in fact you are 100% correct the DSB as working as it should, but therein lies the problem..

John

 

Hey JohnO,

I re-read this message this morning, and realized that I had an answer for you, but hadn't posted it yet. So, here goes.

As I stated before, I keep a 4" DSB in all of my tanks. The reason I keep a 4" DSB is that below 4" is where the anoxic layers begin. Also as I stated before, I've had one of those nasty crashes, and don't ever want another one.[smiley=freak3.gif]

So, to avoid ever having one again, I keep my DSBs at 4". This keeps the anoxic layers from forming, but gives me some of the benefits of a DSB. It is true that I don't get the complete de-nitrification of a 8" sand bed, but I'm not attempting to. I'll stick with a little de-nitrification, and let my live rock and my bio-media packed canister take care of the rest.

Anyway, I just thought I'd throw this out to you. It is an answer for me. Perhaps it could be an answer for a few others out there. 8)

 

I have less then a 2in. bed due to the fact that I run the Eco-System with Miracle Mud. It is recommended that no bed is needed, like the Berlin Method.
So far everything is looking good, except some Cyano which is normal.
[glow=red, 2, 300]I'll keep ya's post on how it does down the road...[/glow]

 

I have a 3" sand bed in my 55g. It's a mixture of Fiji LS and Nature's Ocean white extra fine sand. This is working very well now. I had crushed coral for a while when all the stock was in my 29g. Pulled out most of it and I'm glad I did. Crushed coral is more of a hassel than it's worth - I will never put it in a tank again. Learned my lesson!

Duhjeepster [smiley=cool4.gif] [smiley=2thumbsup.gif]

 

G'Day again Wrassman,

Your solution and thinking of a 4inch bed, supplimented with other filtration is probably the best way to go in the long term.

DSB's are great for denitification and help maintain good water quality. With that said DSB's still have a basic flaw IMO and that is they are waste accumulators. People will often quote them as being export mechanisms when in fact they are accumulators and once they reach a critical stage ( often years ) they will poison your tank.

Now, I have absolutely no problems with people wanting to keep DSB's, in fact my new fug has one. It's just the exaggerated claims that many people make about how they are essential that annoys me a little

John