A Sediment substrate that works

[Maxx]

I'm just not convinced that a system that allows for diffusion of lots of solids into the plenum will be a mechanically sound one....I hope that made sense...

Ahh, I understand now...ya lost me for a second. I dont think that the goal is to let large solids in the plenum, just to find the most efficiant way to remove as many solids as possible.
Thanks for the clarification,
Nick

 

[MikeS]

Ahh, I understand now...ya lost me for a second. I dont think that the goal is to let large solids in the plenum, just to find the most efficiant way to remove as many solids as possible.
Thanks for the clarification,
Nick

Agreed.

I'm just concerned about clogging and unequal diffusion into the plenum during draw off....ideally we want a system that will remove as much of the organics as possible, but we also want a system that is going to be mechanically sound...


MikeS

 

[mojoreef]

Ok I thingk we are pretty close here. Mike organics are going to migrate to the lower region of the SAND substraight of this system through the movement of critters and diffusion just as in a DSB type system. I cannot see any difference in the way this happens in a dsb as to the way it happens here in this system. I dont believe the screen/mesh will have any impact on the diffusion of the system. It will only come into play when the maintence suction occurs quarterly, at this point its a refresh and renew type situation. I beleive at tat point we want to flush the bed of organics and residue byproducts.
To be honest at the point of maintence when the flushing is going to occur I dont see why one could not even stir the bed a bit to help it flush.


Mike

 

[aquariumdebacle]

Either we are trying to remove organics, inwhich case clogging is an issue. Or, as I have discussed with others , we need to remove the break-down products that these organics derive. this means we are removing the dissolved organics, in which case clogging is not as great an issue. There does not need to be a torrent of flow through this system, just enough to keep the organics from stagnating and accumulating. There will be a certain amount of break-down (composting) that a DSB is very good at doing.

 

[mojoreef]

Agreed but I think it should be a little more then just doc's

Mike

 

[MikeS]

what size mesh do you have in mind mojo?

MikeS

 

[MikeS]

perhaps I've been looking at it from a different angle....

maybe the mesh size isn't as important as choosing the correct grain size substrate for whatever mesh we select....

I would say a coarser mesh may work ok if the average smallest grain size is bigger than the opening in the mesh (obviously)...

mojo...on stirring the sand prior to extraction....instead maybe a gentle backflushing of the plenum? This could also aid in loosening any clogs....

MikeS

 

[aquariumdebacle]

Larger grain size = deeper bed

 

[Maxx]

If we backflush, arent we just blowing all the stuff we've tried so hard to get down to the plenum, back into the tank where it came from?
Nick

 

[MikeS]

I'm talking a pretty gentle backflush.....just enough to stir up the water in the plenum and maybe dislodge some of the crud that may have accumulated in the mesh barrier....not enough to actually launch the stuff back into the substrate...

MikeS

 

[Maxx]

Sorry, just had funny mental image of fish crap and other assorted detritus "launched" back into the water column from the back flushing of the plenum. Kinda like a violently overflowing toilet....
Gross, I know, but I didnt get much sleep last night, and the exztra caffiene is playing w/ me...
:lol:
Nick

 

[MikeS]

yeah, that would be bad....:shock:

the backflush is just an idea...I don't know if it's a "good" one or not...

MikeS

 

[NaH2O]

LOL, Nick! I have thought about the backflush, but I don't know if it is necessary. The pieces that are "stuck" I don't believe would find a knew path or move enough to make room for smaller pieces. They would need to wait until they are broken down a little further, IMO. Please correct me if I'm wrong.

 

[mojoreef]

Mike I was thinking between 250 and 300 micron nylon mesh

 

[bobgoode]

Mike, that's the exact size mesh that I'm using in my dsb/p system. Bob

 

[MikeS]

mojo.....that might work.....but I think it would depend a great deal on what size grain substrate we stack on top of it...

Nikki....yeah, I remember you mentioning backflushing earlier...I think it could be ok if done gently enough...probably would not be any more disruptive than stirring the sand up prior to draw off....

Mike

 

[mojoreef]

Hey Bob good to see you jump in on this thread. I know your plenum/sytem has been set up for many years, what do you think about the concept so far???

Ok mike lets talk substraight.


Mike

 

[bobgoode]

Mike, I see no reason why this design would not achieve low NO3's & PO4's.I like it As you know, one must remove the nutrient waste that accumulates within the dsb on a regular basis. My preference is never to disturb the plenum & the denitrifying good guys. On the other hand, I disturb the hell out of the dsb with weekly funnel-siphoning,& stirring which enables removable of PO4-laden detritus & nutrient waste. As we have discussed in the past, bottom-end-cycling is prevented. With regular maintenance, the p/dsb will function for many yrs.....mine's on it's 11th yr. Bob

 

[mojoreef]

Yea Bob your method is really the only sand system that I have seen that makes some sort of sence. Now in this concept we are designing here we are going to be sucking an amount of the plenum water along with any organics that are in region on say a quarterly basis. This would seem to go against your normal practice, do you have concerns in this area???
Also what would be your choice on allow a tiny ammount of organics to be sucked down and through??

thanks Bob


Mike

 

[NaH2O]

Bob - do you replenish your sand critters, and if so do you have a set schedule or just as needed?

Sorry for getting off topic, Mike...I'm curious.