Running a Plenum as an Undergravel filter while cycling

[fudge1]

Superleet,

I dont think it would be such a good idea,if your intention is to establish the bed with the appropriate bacteria while cycling.

In the undergravel,the majority of the bacteria would develop with oxygenated water...end product=Nitrates.

In the plenum,the effect is opposite,with the majority of bacteria working in an anoxic environment,and converting the final Nitrates again into free nitrogen wich escapes the aquarium.

So to me it seems pointless,when you switch to plenum,its like starting over.

JMHO,Marc.

 

[danmhippo]

Do you intend to keep the plenum under your sand after cycling? Remember, Plenum is a pain in the neck to remove especially your sand bed has settled in.

My tank was setup with plenum. I tried to take advantage of the DSB by adding 4" of sand on top of plenum. I do not have a problem with plenum and has no intention to pull it out. Well.....even if I want to pull it out, it would be a big problem as I will have to deal with detritus being stirred up and re-arranging the whole tank. Not worth it IMHO.

Whatever you decide to have as your final layout, do it right from the beginning. HTH

 

[Anonymous]

Maybe an explanation of the Microcean?

Jaubert's true "microcean" system requires considerable effort to set up initially, but can yield stunning systems. It will not function properly with a protein skimmer or addition of calcium ions through kalkwasser, etc. The Jaubert system eliminates the need for any additives through a budget of carbon and nitrogen. Protein skimmers remove this necessary carbon. When set up correctly (approx 1-2" plenum height, and 4-5" deep sand bed per 100 gallons roughly; Seaflor and crushed coral are the best substrates; strain it through a 2 mil strainer though, to avoid getting too many smaller particles). The organic acids produced in the sediment bed (and diffused underneath) dissolve the aragonite. Its components are diffused (another important reason not to have too much fine sediment) to the surface, and are distributed into the water column by using high energy flow/surge above the sandbed. This works very well even for fast growing SPS. The imperative thing to remember is to have a large surface area of sediment sand and a good volume of plenum water. There are two good ways of doing this. One is to have very little of the sandbed covered by live rock (not often an option), Two; have the live rock elevated off the substrate (getting warmer...) or to have an supplemental Jaubert tank (kinda like a large sump, with a proportionally accurate plenum/sandbed)...be careful not to compact the sandbed down while you are placing the live rock (also, add no potentially precipitating additives; ie kalkwasser), otherwise, you'll create hydrogen sulfide reactors/pockets. The other imperative thing is NEVER to let light into the sandbed or plenum. This would encourage a growth of phtosynthetics to produce O2 in the sandbed; completly defeating the purpose (O2 concentrations in the plenum and lower sediment bed shouldn't exceed .05 mg/L, nor should they become completely anoxic). Don't stir/vacuum the sandbed or have large animals that would provide excessive bioturbation.

 

[Reeffreak]

Galleon,

That is one of the better plenum explanations that I have heard!

Steve

 

[SuperLeet]

Thanx a lot for the explanation, I was just curious because of GARF's bullet proof reef said to do that. I didnt agree so i took it here!

 

[fudge1]

Galleon,

Excellent plenum description,but what ya make of the question?

 

[Anonymous]

Hiya Marc, long time. "The answer is only important if you ask the right question."

I would say its pretty much a waste of time to run it as a UG filter, as you will incite culture of aerobic organisms that will die and only create further bioload when you cut it off. Basically, I agree with Marc 100%.

 

[fudge1]

<BLOCKQUOTE><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><HR>Originally posted by galleon:
<STRONG>Hiya Marc, long time. "The answer is only important if you ask the right question."

</STRONG><HR></BLOCKQUOTE>

Amen!,but how does one gain knowledge if no wrong questions are ever asked?

Ok,ill let it go this time....but only `cause your plenum description kicked a$$.

Marc.

 

[SuperLeet]

would there be any adverse effects of doing this? Would there be any advatages?