Live Sand or Bare Bottom

[WaterKeeper]

Their burrows range from 4"-9" deep so a 4" bed is somewhat pushing it as they grow. One of the things a Jawfish does is move sand about, some people feel too much, so there is little chance at dead spots in a 6" bed.

[beelzebob]

when i started out, i considered going with a BB.

but due to my inexperience, the fact that detrius is easier to see on a BB, and the fact that i found some super sweet black sand.

now i have a 3"-5" DSB and i love it.

i think its really a matter of personal preference, not one bettr than the other.

its like two people arguing over wheather a lime is better than a lemon.

do your own thing! i love my black sand. don't see much of it at all in the hobby.

you do hear a lot about how BAD it is, and how the other white sands are BETTER.

it all depends on the orientations of your goals.

are you more concerned with asthetics or mechanics?

i went w/ asthetic appeal.

[MJinMN]

I thought there were a lot of folks who like a SSB in the main display, and run a DSB in the fuge. Where are all those people?

[dippin61]

well.. ill tell you this. about a year ago, i got a different job then the one ive always had, and have again. The tank went un-maintained for about 3 months. (no water changes, no cleaning, no siphoning, nada, top off water every once in a while). and i got the tank to bounce back from a HUUUUUGE hair algae problem, in about month, month and a half.

now, with a dsb tank, theres no way it could of gone that long without any maintenence, then bounce back so fast, with little to no effort. Trust me, i tried with my old tank when it had sand. thats what made me go to BB in the first place. my tank got neglected, and it took months and months and months, to get it to look less crappy, but it never looked as good.

JME at least

[trothatl]

Beelzebob, why do some people say black sand is bad? I hadn't heard that before (but I'm still new to all this and have only been researching and lurking in the forums for a couple of months).

Also, in this debate between BB and DSB, are you all including plenum systems in the DSB category, or do you consider that to be an entirely different creature? I'm in the process of planning a 72-gallon tank (my first SW) and have found this thread to be very interesting as I go about deciding on setup options.

[beelzebob]

black sand doesnt (usually) possess the same benificial chemical properties that aid the nitrogen cycle, and in maintaining a healthy equilibrium of these vital chemicals.

i think.

[beelzebob]

ask WATERKEEPER.

his two cents can be worth millions.

[WaterKeeper]

OK,



There you go.

The sand one wishes to have in one's tank is the same as that covers the ocean floor--namely aragonite sand. Now aragonite is 99+% calcium carbonate, a beneficial mineral in helping maintain pH and buffering ability of the tank's water.

In a shallow sand bed the pH pretty much remains in the range the tank water 7.8-8.3. At that high pH calcium carbonate just sits there and does nothing. In a DSB however as one preceded deeper and deeper into the bed oxygen is depleted and eventually become anaerobic. No matter what material is used for the bed, as oxygen nears zero, the bacteria in the bed then use the oxygen in nitrate to metabolize food. This reduces nitrate to free nitrogen gas that then bubbles out of the tank. This, of course is a good thingy, and it will happen with any fine sand, not just aragonite.

Once all oxygen and oxygen carrying compounds are removed then we have true anaerobic conditions. Here things change. Acids such as acetic (vinegar) are produced and the pH falls. Often well below pH 5. Here is where aragonite sand shines as it will dissolve and react with the acid. This releases calcium into the water and helps keep pH from further decline. Also the calcium acetate formed will be assimilated by bacteria and the acetate portion used to maintaining buffering in the tank. It is a pretty sweet deal. There are no hard studies to see how great a benefit this provides but I would have to believe there is some.

Overall, if you use fine beach sand you'll get the desired nitrate reduction but it will not do anything toward calcium replacement or pH stabilization. That is true of the black Obsidian (?) sand mentioned above. All it means however is that you may need to add buffers and calcium more often than those with a true aragonite bed.

I'll be waiting for my check Bob.

[trothatl]

Excellent explanation! I knew there was a chemical difference between regular aragonite sand and black sand, but I didn't realize aragonite had such an impact on water chemistry. I thought the main issue was to be careful about using silica sand. Somewhere, some time ago, I read an opinion that aragonite really didn't have much effect on water chemistry and that stuck in my head.

Guess I need to start hanging out over in the Reef Chemistry Forum!

[AZDesertRat]

dippin, what maintenance are you talking about? I keep seeing all this talk about maintenace and still say its pure BS. I do NOTHING and have never done anything with my 100G in the 3 years it has been up. I am very lax about water changes and it still looks petty good.
Tell me what maintenance you are trying to feed everbody! There is no maintanance, thats why they are so sucessful for newbies. I think you would really have to screw up to fail a with a proper DSB. I suppose adding sand sifting stars and digging fish can lead to a failure but with proper husbandry its pretty tough to mess it up.

[EdKruzel]

Originally posted by trothatl
I thought the main issue was to be careful about using silica sand.

That was a comment stirred by hobbyists confused between silicates and silica.
Silicates are used to feed diatoms and cause that huge "brown Algae" bloom usually in new tanks.
Silica is most often used for clean sand blasting; it takes a significant acid (like sulfuric acid) to dissolve this sand.
It works great for a DSB, but does not provided the calcium so many wish for as Tom mentions above.

AZ,
I don't see any need for maintenance either; just let the worms and pods do their thing!

[zacharytrimble]

Sandbed is good if you want corals or if you want to keep fish like mandarins....the 'pods' they eat will multiply more than if you have bare bottom

[WaterKeeper]

Just to add onto Ed's remarks. Silica found in minerals is just like the glass in your tank. It doesn't dissolve in water. In fact even concentrated hydrochloric, nitric, phosphoric and sulfuric acids are sold in glass bottles. Only hydrofluoric and sodium hydroxide attack it to any great extent.

Doc Ron use to say that the sharp edges on silica sands could injure organisms but I really don't see that as a great problem. The sharp edges do tend to cause friction between grains and slow up bed migration. I'm sure the higher density of silica to carbonate sand also impedes sand stirring. However, none of these factors make it unsuitable for tank use.

[trothatl]

Tom & Ed, I see your point about silica vs. silicates. The concern that I've read about the use of regular silica sand is the possibility of contamination from other minerals. I've seen entire threads on how to locate a particular brand of playground sand, or the use of masons sand vs. playground sand.

Now that you mention it, though, I have seen people say that silica sand will release silicates. I've quiclky learned that in reef-keeping you shouldn't take any one opinion as fact! But I guess that applies to the Internet as a whole.

[bertoni]

Silica sand can release silicates, but it's not clear that's an issue. Freshly-ground sand is more likely to do that.

[WaterKeeper]

Yes, I stand corrected Jon. Some sands do contain Sodium Silicates which were formed when igneous rocks were formed (sodium carbonate + silicon dioxide + heat ----> sodium orthosilicate and other silicates). The sodium silicates are soluble. As Jon points out washing the sand will remove most of it.