algae barn vs BRS rock

[GlassMunky]

"
From previous experience, 0.25–0.5 kg of LRs is needed for every
liter of water (Delbeek and Sprung, 2005), indicating that LR in
the aquarium can provide sufficient ammonium removal activity.
Yuen et al. (2009) found that LR can effectively control am-
monium, nitrite and nitrate in water. In a system with LR, the in-
organic nitrogen released by sea cucumbers can be removed by
LR effectively. LR can also effectively maintain the pH of the wa-
ter. However, no significant nitrate removal was detected in our
study. The possible reason may be that the concentration of the
added nitrates was too high. In the nitrate addition experiments,
the amount of added nitrates was equivalent to 6 mg/L, which is
much higher than either the nutrient level in the temporary cul-
ture tank (NO3–<0.3 mg/L), or the required level for coral reef cul-
ture (Delbeek and Sprung, 2005), or the average level in com-
mon reef water (Wang et al., 2002; Peng et al., 2002), or the peak
nitrate level in Yuen′s experiment. At such a high substrate con-
centration, the degradation rate of denitrification may not be ob-
served; therefore, further analysis is warranted in future experiments"


from the paper.....

 

[GlassMunky]

meaning they have no idea why they are seeing what they saw and even by their own admission it needs further study.


so why are soo adimate that you know exactly whats up when even these scientists say they dont know?

just so you can be right?

 

[danimal1211]

1-2lbs is certainly more than adequate for conversion of ammonia to nitrite and from nitrite to nitrate. In fact that process can be handled by much less. That however is where the process stops in any significant amount time and time again and some other form of nitrate removal's is necessary. The premise that 1-2lbs of rock will sufficiently convert nitrate to nitrogen gas is baseless regardless of porosity. Live rock (at least in the capacity we typically keep) can’t sufficiently convert nitrate to nitrogen gas by itself.

The conversion of nitrate to nitrogen gas within the pores of live rock has not been observed in any significant amount by either study nor by aquarists. Continuing to sell the idea that porous rock is somehow>less porous rock or that 1-2lbs will sufficiently remove nitrates is antiquated and based on a false premise.

 

[mook1178]

meaning they have no idea why they are seeing what they saw and even by their own admission it needs further study.


so why are soo adimate that you know exactly whats up when even these scientists say they dont know?

just so you can be right?

As a scientist myself, I read that section as denitrification may be happening in LR, but not at a rate that is sufficient for removal, which I would agree with just from anecdotal aquaria hobby evidence. If LR could denitrifiy at a high enough rate to remove nitrates from the water column, then nitrates would not spike in aquaria like they do.

 

[PotatoPig]

The conversion of nitrate to nitrogen gas within the pores of live rock has not been observed in any significant amount by either study nor by aquarists. Continuing to sell the idea that porous rock is somehow>less porous rock or that 1-2lbs will sufficiently remove nitrates is antiquated and based on a false premise.

I’ve always been a little skeptical of the benefits of porosity - those pores are mostly getting fairly promptly plugged by algae and detritus anyway, then getting encased by coralline algae and encrusting corals.

 

[mfinn]

From the pics BRS looks a bit more aesthetic, but AB is so much cheaper for 90 lbs. I figure once the coral starts really growing I won't be seeing so much of the rock and it won't matter.

Is one inherently better than the other for any reason?

Go with the one that looks better to you. It does matter.
It may take a few years before the coral growth is good enough to cover the rock, so you are going to be looking at it for a while.

 

[jda]

There have been studies and experiments back to the 1960s that show that porous live rock with more than an inch from the surface does indeed denitrify. Non-pourous rock does not do it very well. Nearly all studies or experiments that show one or the other likely used different types of aragonite or calcite of different porosity. Wet Web Media had discussions about this and stuff.

Beyond denitrification, the pores can help microfauna have homes, live, breed, etc. The pores trap things for the microfauna consume and digest. Sponges can root in the pores.

I doubt that any rock can remove no3 as well as sand can, but there is a large difference between something like Marshall Island and the man made concrete decorations that people call rock nowadays. The fact that some people using terrestrial mined rock needing sometimes years to get the pores unclogged do eventually see nitrate lowered over time is pretty good evidence too.

 

[jda]

Dr. Randy Holmes-Farley has long (at least 20 years) supported that denitrification does not have to happen too much in the tank so long as it is located in very close proximity to where the no2 is created. The synergy of having NOB on/near the surface of the rock and anoxic bacteria nearby makes the whole process more effective.

In the end, bare bottom tanks with lots of real live rock will keep no3 lower. A little sand helps too. More sand helps more.