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Discussion Starter · #1 ·
I have been told 2 different things on this subject. Lets see what all of you have to say about it.
One place told me to have a thick sand bed about 4 inches.
Another place told me to have a thin sand bed about 1 inch.

What does everyone think and why? Does tank size make a difference? Thanks for posting!
 

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I have been told 2 different things on this subject. Lets see what all of you have to say about it.
One place told me to have a thick sand bed about 4 inches.
Another place told me to have a thin sand bed about 1 inch.

What does everyone think and why? Does tank size make a difference? Thanks for posting!
I think it all really depends on what you wanna keep in you're tank
 

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SandBed

I do .25 of an inch just to cover the bottom. I have never had to vaccume or had an issue. It provides more space for the fish and cheaper up front. Furthermore sand does need to be replaced a years down the road. Not a fan of DSB in display.
 

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The best reason for a DSB is nitrate export.

A deep sand bed (>4") will not allow oxygen to the bottom of the sand. There are great bacteria that eat nitrates but they don't like oxygen. The bacteria changes the nitrates into nitrogen gas which bubbles up to the surface. If the sand bed is stirred up or the bacteria dies it can cause huge problems including releasing hydrogen sulfide or starting a new cycle. So we really like that a dsb gets rid of the unwanted nitrates but it does have risks.

It is usually not recommend to do a 4" dsb usually they want to be deeper 6-9" for proper stratification.

So, you actually have 3 options; bare bottom, shallow sand bed (1-3"), and dsb (5-9"). It all depends on the animals you want to keep and the aesthetics you like.
 

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Discussion Starter · #6 ·
well here is what I am dealing with. I have a 180 tank and want to use that real fine sand. I like the look of it. It will be a reaf tank, but not sure of exactly what I want to put in it yet. I have a couple tangs from my 90 that will go in it, along with hermit grabs, some snails, cleaner shrimp.

should I use that real fine sand or should I use crushed coral? And I still dont know how deep to make the bed
 

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+1 DSB. Though, my current sand bed ranges from about 3" to 6 inches depending on where the goby I had wanted to push it all to.
I wouldn't go with the real fine sand. If you plan of having a decent amount of flow then it will be blown all over. I would go with a heavier grain size like the special blend. Nix the crushed coral.
 

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As touched by other posters, different types of bacteria live in different areas of your tank. You want them all, so you should provide places for all of them to live.

The best way to do this is to have a varied size sand bed. It should be made up of very find sand, all the way up to a crushed coral. I don't suggest much crushed coral because crushed shells are notorious for cutting the bellies of gobbies and other soft sand dwelling creatures.

I suggest having your sand bed be nice and shallow up towards the front, say 1" to 2" with gentle slopes reaching up to 4" or so. Have the back of the tank be deeper. Make it between 4" and 8" with slopes in between. Also if you have room in your sump, take a 5g bucket full of sand and run water over that. That is called a remote deep sand bed, it will help remove nitrates as well.

If you decide to go with a shallow sand bed in your display, remote deep sand beds are the way to go. You can also build a coil denitrator, and/or a sulfur reactor to help. I love bio pellet reactors, but they don't really do much for the type of bacteria you lack in a bare bottom/shallow sand bed tank.

It all comes down to your personal preference and how much time you have. Many people choose shallow sand beds because you don't see all that sand in your tank. Those people have to do more work to keep their parameters in check.

Other people opt for the easier to manage, but potentially less appealing deep sand bed. It may not be as pretty, but it is a whole lot easier to maintain, and because of that, everything else in the tank looks better.
 

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Substrate

Snyd09, as you have probably picked up, both of what you were told about sandbed depth can be correct. Part of the decision is personal prefenece for the look of the tank and part is a functional decision.

To be clear (and maybe a little picky) , DSB's serve the purpose of denitrification or "natural nitrate reduction" as opposed to "nitrate export" which is a term usually associated with the removal of macro-algae from a sump (hence removing the nitrate that the macro-algae absorbed). The aenerobic bacteria that live in the oxygen free zone of a DSB convert nitrate to nitrogen gas and water as part of the nitrogen cycle like LR does. Unfortunately, a byproduct of this process is the formation of hydrogen sulfide which is toxic to fish. One concern that some have is that if the DSB is disturbed there will be a release of this material.

This topic is widely debated in the hobby but I think you will find that in general a DSB is defined as being about 4-6 inches in depth. It is best made up of sugar fine or oolitic aragonite. The smaller the particale size the better since larger particle sizes allows oxygen to penetrate further into the DSB defeating it's purpose. Basically, the denser the better. This does create a problem though in high flow systems that have a higher opportunity for creating a sand storm with the fine substrate. This is why many, and I include myself in this, recommend the DSB be housed remotely in the refugium/sump, or other container outside of the display. I personally always had mine in my refugium.

I do agree with others that you generally want to avoid crushed coral for reasons that you can read about but that include the crud capturing ability of CC. I prefer
1mm-2mm aragonite and I think you'll find that pretty common.

The other reason to have a DSB in the display is to house critters like jawfish that need that depth.

If I were to make a recommendation(and this is what I did in my 180g) I'd say use about 1" of 1mm-2mm aragonite in the display and employ a decent size refugium with a DSB of sugarfine sand greater than 4" for both denitrification and micro-fauna support.
 

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To be clear (and maybe a little picky) , DSB's serve the purpose of denitrification or "natural nitrate reduction" as opposed to "nitrate export" which is a term usually associated with the removal of macro-algae...
Hmm, I stand corrected:rolleyes:

Snyd09, I highly recommend caribsea fiji pink. Small grain size but big enough that it doesn't cause dust storms.
 
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