Dsb's work, what makes them work best?
- Thread starter barryhc
- Start date
<a href=showthread.php?s=&postid=6492309#post6492309 target=_blank>Originally posted</a> by barryhc
But ( hehehe ), wouldn't this mean that since Araganite is better at adsorption, that it would than retain more phosphate over a period of time, and that silica, since it is not adsorbing as well, would allow more phosphate to be processed in a different manner, including more "release back into the water column", at least initially?
I mean doesn't the Araganite act like a sponge, more so than the silica, and isn't this why some newbies, or others, get away with over-feeding for a while, and then the sponge fills up from this, and can't cover up the "indescretion" any longer?
And I like your recipe too, but I still have a lot of interest in substrates, and grain size. Maybe Bertoni, or someone else will show u pwit hsome good information here. I continue t obe concerned about "mud" sized particles.
While we're at it, I need a primer, on aDsorbed vs aBsorbed. "Weatherman"?
Thanks > barryhc
In the beginning, aragonite is better for the reason you mentioned and because it helps the bed get established faster IMO. Knowing that aragonite is going to automatically come with it's hitchhiker phosphate, I don't really care. Most people were trying to go to a sediment that doesn't have carbonate bound phosphate as a solution. But it really isn't a solution long-term.
Yes, in the beginning an aragonite bed will be more forgiving of a Newbie as well. However, like your sponge example points out.....it's not really helping the newbie. It's just delaying the inevitable when they will find out that they were overfeeding all along and/or not avoiding P inputs. Depending on the types of corals you keep, this can be a dangerous practice.
My "recipe" for a DSB tank is exactly the same as BB tank. Our skimmers aren't 100% efficient, bacteria aren't 100% efficient, if you can grow macroalgae in a refugium, then you clearly have phosphates in your water column don't you?
Phosphates are limiting. I wasn't necessarily saying that you had huge amounts of phosphates. I was just pointing out that there are phosphates in your water column.
People tell me that sandbeds and LR don't release phosphates. Then they say they utilize skimming and refugiums to remove phosphates. There's only one way for phosphates to get from the LR or sandbed to a refugium or skimmer.....through the water column.
kbmdale
In Memoriam
OH I agree.. There are always phosphates in the water, just at safe or undetectable levels. I just thought it alittle missleading the way you stated it. Sounded like you were telling people if thier macro is growing something is wrong, which is not the case. If your macro is growing but your not getting any algae bloom in the main display then it is doing its job well... Macro is more for nitrates IMO than phosphates.
Weatherman
New member
It is?
Then why even bother with a sand bed at all?
RichConley
New member
Now, I'm assuming it has been established that silica sand doesnt lock phosphate like aragonite does, so here is my question. In reality, what is the difference between a aragonite bed with locked phosphate, and a clean silica bed. If its in the bed, its not affecting your corals. If you add phosphate to either system, the same amount ends up in the water.
I'm probably not being clear with my wording above. IE what different does insoluble phosphate in your sandbed make?
The aragonite will fix phosphate in the beggining, where as the silica will not, but this seems like a good thing to me. You get some phosphate buffer in the beginning with the aragonite, and after that, they both act the same. Am I wrong here?
Putting coarser substrates on top is unnecessary and possibly counterproductive, IMO. Often, the goal is to reduce sandstorms, but the larger grains at the top can effectively kill the rest of the sandbed by providing an unliveable environment for bioturbation. So this is the recommended distribution for grain sizes, from Dr Shimek's booklet. I've translated the fractions to decimals, so ignore all the precision:
40%    0.125 - .0625mm
30%    0.25 - 0.125mm
15%    0.25 - 0.5mm
10%    0.5 - 1.0mm
The rest is > 1mm.
As far as keeping the sandbed alive, if not much food gets there, you won't have much life, but I doubt that's an issue in most any real tank since our tanks are so overstocked compared to nature. In the end, though, you do have to feed to keep the sandbed alive, so I add food to tanks with no fish, etc, that are in holding patterns for just that reason.
<a href=showthread.php?s=&postid=6486098#post6486098 target=_blank>Originally posted</a> by Sindjin
ISo far we have learned that PO4 bonds to things dependant on other things....but never really gets "dephosphatized".
I disagree. Why do you say that?
My sandbed maintenance consists of adding a recharge pack every couple of years.
Weatherman
New member
<a href=showthread.php?s=&postid=6493008#post6493008 target=_blank>Originally posted</a> by barryhc
Why can't this antagonism cease?
> barryhc
Not antagonistic. Just a simple question.
If you are going to use macroalgae to reduce nitrate, why use a sand bed?
I see where you are coming from Rich.
It's more complex than you might believe. Chemical reactions IN THE BEGINNING will allow adsorption with aragonite. It won't happen IN THE BEGINNING with other materials.
However, after a period of time, we leave chemical reactions for the most part. Bacteria will take over and they like to mess with simple chemical reactions. In my tanks, I've found that they won't listen to a thing that I say. I've even wagged my finger at them and said, "Baaaaadddd". They didn't listen.
After time, in non-carbonate substrates, the P will be processed amongst the bacteria and critters. In carbonate substrates, the P will be processed amongst the bacteria and critters. Some chemical reactions will occur but will be hampered by the bacteria for the most part.
This issue actually came up in Dr Holmes-Farley's tank. After he started using a macroalgae refugium, his DSB seemed to show a lot less activity.
I would continue using a DSB for the food production and because of the interesting animals in it, although some tanks might need the extra filtration.
