The Great Sandbed Debate

[Larry M]

First, let me say that I have four tanks--two have deep sand beds (4+) inches, and two (The FO and my 6 gallon nano reef) have shallow beds (1/2-1"). While I'm sold on the idea of a deep bed being great for denitrification, I'm not so sure that the advantage outweighs the cost, or even risk, of a deeper bed. For example, the two tanks with deep sandbeds constantly have diatoms on the glass, and need to be cleaned every 3 days or so. The two tanks with shallow beds don't have this problem. I may clean the glass every two weeks, is all.
I have added detritivore kits (tiny brittle stars, varieties of worms) to both of the deep-bed tanks, and I try to feed them what I consider to be quite a bit, in the hope of nurturing the sandbed critter population. Still, I have to say I don't see a whole lot more life in those tanks than what I see in the others. And I have this diatom thing going on that can be annoying.
Can I deduce from my observations that I can have a tank that is nearly as diverse, and easier to maintain, with less risk for sandbed fouling, by using a shallow sandbed? Or am I asking for trouble in the long run using a shallow sandbed?
Any input?

Larry[/]

 

[hcs3]

larry

as you know, i look to mike for my help on sandbeds. and i bet this topic will get his attention as soon as he gets time from moving. but, as i see it, i can still offer my view...

first, i think a shallow and a deep sand bed can both work equally as well. just that the hobbiest attempting each knows the +'s and -'s involved. it's already been proven that you really don't even need a sandbed at all, as LR alone can do all of the filtration. a sandbed can be just enough of a covering so it looks natural. to me, plain glass is very boring, and not realistic. once i remember hearing of someone that had green star polyps across the entire glass bottom... anyway, these style tanks made for easy detritus removal. the tanks could remain *pristine* in a sense. this tank, as successful as it may be, will never be able to contain many varieties of animals that many would consider desirable eg., tiger-tail cucumber, wrasses, mandarin, etc... a thin sandbed opens up a larger scale of animals acceptable, and once again, looks more pleasing to the eye. does it effect denitrification in any way? probably not. still again, desirables can still be missing from the equation. with a deep sand bed, you accomplish many things....first, certain species of wrasses are now attainable. all species of animals can be accounted for. it brings you one step closer to nature. animals that normally you don't see, eg. brittle worms, brittle stars, pods, etc., (i could go on, but i think you get the idea). for me, the closer to nature i am, the better off i feel that i am. even though a shallow or non-existant sandbed can work, i think it is missing way too many of the "no-see-ums" that it pulls us that much closer to an artifical environment. of course, with a deeper sandbed you also now have additional denitrification available. here is a link...

http://www.reefs.org/library/talklog/r_shimek_090698.html

i think you've seen this before, but i'm supplying it for all the other readers. it is written by ron shimek. i see he has visited here already, so maybe the thread will get his attention. matter of fact, i better shut up. i don't want him making me look THAT stupid.

henry

 

[billsreef]

Larry,

For some reason my experiences with shallow vs. deep sand beds tends to run opposite to your problem. Currently I am running 1 deep bed (4+ inches w/plenum) and 1 shallow (1 inch)sand bed with no problems in either. In past tanks when I have had diatom problems I used pH as an effective control as outlined in TRA 1.

Bill

 

[Larry M]

I know this subject has been gone over about a million times, so I won't feel too bad if people don't flock to join in.
Bill--My TRA Vol 1 is loaned out right now, but I'm guessing you're referring to an elevated ph controlling diatoms. That's another of my problems--I have a hard time getting ph over 8.15 in any of my tanks. Did I mention that venting my skimmer outside did nothing for that?
I guess I may have to break down and resort to dripping kalk.
Larry

 

[DougL]

Larry;
I think that most of the infauna will be found in the first inch of the sandbed.
Since they are all aerobic, it passes common sense. Therefore, diversity should be about the same. The difference will be
nutrient recycling. From what I've read, the nutrient recycling isn't optimized until you have H2S pockets in your sandbed.
perhaps you are seeing silica recycling on your 4" sandbed.
I am personally intrigued with the deep sandbed, but certainly it will run either way.

Hope this helps;

DougL

 

[cjdevito]

Just a quick link here:
http://www.reefkeepers.org/faq/cache/33.html

This is a summary of a basic overview of deep sand bed methodology that I put together for a series of posts to rec.aquaria.marine.reefs last year. Jimmy Chen put it up on the reefkeepers site and broke it up into a lot of mini-pages, but the content is still there.

Anyways, this doc includes pointers to a number of works by Ron Shimek and Rob Toonen. It's far from comprehensive, but I'd call it a good entry-level look at deep beds.

 

[MIKE]

Well now....

I had to stop packing for this one

Larry, you say you're not sure the benefits outweight the risks. What risks? Have you ever seen a tank "crash" because of a thick substrate? I haven't (at least one that was done properly).

You say that you have diatoms in the thick substrate tanks. The implication, I think, of your statement is that the thick substrate is causing the diatoms. If that's what you are saying, isn't this a bit of cause/effect thinking that gets some of us in trouble some times?

As far as diversity. At a minimum, I can guarantee you on the thin sandbed, you'll lack the anerobic bacteria necessary for denitrification.

JM2C
Good luck
Mike

PS back to the boxes!

 

[Larry M]

Thanks for the replies. To be honest, I was really trying to bait Ron into answering.

But I'll go back and read those articles again too.


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Larry M

Visit Reef Central's Home Site at:
www.reefcentral.com

 

[FishDaddy]

Hey Larry,
When you get through reading those, here's the whole collection!

http://sites.netscape.net/douglxyzzy/sandbed.html
Dick

 

[FishDaddy]

Larry,
When I looked at Doug's site again, I noticed it didn't have Charles' FAQ! I've sent the link on to him so his reference page will be complete!
Dick

[This message has been edited by FishDaddy (edited 10-05-1999).]

 

[DougL]

FishDaddy;
That's a good site!
Thanks for pointing it out.

Later;

DougL

 

[MLP]

Hi Larry,

Well I am running a 4" substrate bed in both my current tanks. One with a plenum and one without. I hve not had a diatom problem since shortly after set-up in either. The same goes for hair algae and cyano. Once I made it through the initial blooms, no more problems.

The part that surprises me most about this in my systems is I use only tap water for everything. I consider myself one of the lucky few that has very good quality water right from the tap. Definatly a minority!!

For me I feel that the advantages that come with a deeper substrate bed outweigh any negatives, and IMHO the negatives are very few.

Good Luck

------------------
Happy Reefing,
Michael
mlp@aquariacentral.com

Learn form the mistakes of others, Life is too short to learn them all for yourself!

 

[billsreef]

Larry,

Your guess is right. When I was fighting those pesky diatoms (the kind that kill snails) I used the elevated pH along with a reduction in photoperiod, a week of 4hr days started by a day of no lights. To keep the pH elevated I was dosing kalk 2 to 3 times a day, basically anytime I walked passed the tank. It was a royal pain in the a** but it worked.

Bill

 

[Kirbster]

I don't think an inch is going to have nearly the diversity of a 3+" bed. Disregarding the anaerobes, and focusing on the "infauna". With good initial seeding and other favorable conditions (adequate nutrients, temperature, etc.) it would probably generate decent diversity initially, but the sheer numbers would be less and the addition of a low level predaotor (such as a small wrasse) could wreak havoc on certain populations. The worm action oxygenates and loosens down to 3 inches pretty well, which creates additional living quarters AND a kind of "safe place" for burrowers.

I had a 36x18 inch tank with a rougly 2 inch bed that had dissolved to about 1 inch over the years. There was plenty of diversity and things seemed fine. the only residents were a Candystripe Angel (Centropyge eibli) and a pair of Ocellaris clowns. In a fit of apparent madness I aded a little Pseudochelinus wrasse (Scarlet Wrasse, I believe the common name was). These wrasses aren't sand sifters, but within 8 weeks, my sand bed's diversity was pathetic.

In contrast, I have some 48x18 tanks with 3 to 4 inch beds that support numerous preadtors and seem to maintain decent diversity. I think the depth helps the sand fauna in this respect.

My 2 cents.

KA

 

[Kirbster]

Larry,

You went about baiting Ron the wrong way.

You have to say, "Sand beds do best at 72F with an SG of 1.017 and with minimal feeding."

That would bring him out for sure!

KA

 

[Larry M]

LOL
I think I know another way too:

"What the heck kind of polychaete is this anyway??"

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Larry M

Visit Reef Central's Home Site at:
www.reefcentral.com

 

[Larry M]

Ahhhhh! You got me there, Ron. I have a ton of excuses at the ready, but instead I'll just promise to catch the next class.

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Larry M

Visit Reef Central's Home Site at:
www.reefcentral.com