Re: [RML] Fluidized bed vs. Wet/dry

Bjorn Straube (straube at digital.net)
Tue, 27 May 1997 21:43:33 -0400

Mike Adams, Jr. wrote:

> Is this Jaubert System the live sand with a plenum underneath. I've
> considered this for freshwater but only as a means to cheaply install an
> undergravel heating system by providing a dead space beneath the gravel
> with the use of egg crate and nylon screen and placing the heaters there.
> I'm reluctant to do that, however, because of the reduced accessibility of
> the heaters. But in response to your main point, I'm not sure why the
> biology would be any different in fresh than it is in marine insofar as the
> role rock may play in providing filtration, given your description of the
> denitrifying potential of the inside of live rock is correct.
>
> Mike
>
> -----------------------
> Mike Adams
> University of Kentucky
> College of Engineering
> 606/257-4093
Yes that is the system. If you put heaters under it, the purpose of the
whole nine yards would be defeated. This is because water, and the
oxygen in it, would circulate through the substrate and arobic
conditions would prevale (sp?). But if all you wanted was and under
gravel heatering sys then I cann't see why it would not work. BTW the
nylon cross stitch/craft "fabric" works better than widow screening
(IMHO) because it stays put once a little wieght is put on it, its also
easier to size.

Craig Bingman wrote:

> It isn't that porous, and I think the denitification potential of live
> rock is usually overestimated. It is variable. It also might be
> difficult to find appropriately porous rocks for a freshwater tank that
> were not made of calcium carbonate.
>
> That does work. Which is why I suggested a deep bed of coarsish gravel
> for fishtanks. The gravel in our freshwater tank always has gas bubbles
> in it, which I presume are mainly nitrogen.
>
> One caveat that you should be aware of... when denitrification is going
> ina system, there is generally some nitrite around. That isn't a big
> deal in marine systems, since Cl- competes with NO2- for uptake.
> However, it might be a very big deal for freshwater systems.
>
> Craig
>
I'm not sure how to respond about poracity of live rock, the rock I
have is very porous but some of it was not "live" when I put it in, it
was coral ruble. Most of the texts that I have read claim live rock as
porous and I would trust them on it, but thats personal :) As to a
porous rock that is not calcium carbonate mabey lava rock, I have no
idea what it is made of, any geologists out there? Lava does not have
the characteristic white color that I think of when I look at calcium
carb. You may well have a good point about the nitrite though, I had
not really considered it. I'll have to look into it before if I ever
get around to seting up another "experiment" ;)

It's been fun
Bjorn