Fluidized Sand Bed Help

[MikeFellows]

I picked up a second hand Fluidised Sand bed to attach to my sump, the problem I have is it came with no instructions

I bought some sand up to go with it from the local LFS

but I have no idea how much or how little to put in it!

any advice or help would be great

Thanks

Mike

[WaterKeeper]

As the Master Jedi one said, "Paul B it is who you seek".

Here is a little that he wrote about reverse flow beds in an old thread of mine Paul B, RUFG's.

[jamiep]

I'm not an expert on this but as far as i know how much sand you use depends on your flow through your sand bed so I would say add slowly until it is in a good motion. You don't want to much flow that it blows the sand out, or too little so that the sand doesn't move, but one thing to consider is that it will take slightly more pressure to get the bed moving to start off so you may need to install a ball valve. But as I say ive never used or set one up so I'm no expert

[MikeFellows]

Waterkeeper you are a legend

i spent most of last night reading your thread and was excellent

I now have a good idea what im doing, and im also going to resurect my old canister filter from my tropical days

Thanks again

Mike

[WaterKeeper]

Well thanks Mike but we are still waiting on Paul to chime in here. Oh Paul, where are for art thou?

[capn_hylinur]

me too--entertainment for us "aging" reefers

besides I just looked in a bag of aquarium junk I got at a flea market---there is a fluidized sand bed in there--that looks useable--especially in the light of that other thread.

[Paul B]

Ahh Watersnorter you never cease to amaze me. I have a job for 15 more days (then I will be retired)
I actually don't spend all of my time on RC.
A fluidized sand bed has nothing to do with UG filters but is a novel, kind of wierd IMO useless, filtration device that came out a number of years ago. It is filled with sand and water flows through it, causing a mini typhoon of sand. The theory is that the bacteria adheres to the sand grains and since they are in motion all sides of the sand and therefore the bacteria are exposed to the oxygenated water. It has the same effect of a wet dry only more dramatic. Just fill it with enough sand so that it does not expel the sand out of the filter and adjust the water flow so most of the sand is in motion. Get yourself a nice drink and stare at it. It is probably a very efficient aerobic water conditioner.

[capn_hylinur]

Originally posted by Paul B
Ahh Watersnorter you never cease to amaze me. I have a job for 15 more days (then I will be retired)
I actually don't spend all of my time on RC.
A fluidized sand bed has nothing to do with UG filters but is a novel, kind of wierd IMO useless, filtration device that came out a number of years ago. It is filled with sand and water flows through it, causing a mini typhoon of sand. The theory is that the bacteria adheres to the sand grains and since they are in motion all sides of the sand and therefore the bacteria are exposed to the oxygenated water. It has the same effect of a wet dry only more dramatic. Just fill it with enough sand so that it does not expel the sand out of the filter and adjust the water flow so most of the sand is in motion. Get yourself a nice drink and stare at it. It is probably a very efficient aerobic water conditioner.

Paul--congrats on your upcoming retirement.
Beware---I retired from my first job(33 years) for exactly one month--only for a private institution to make me an offer I couldn't refuse--and there is still not end to it

Waterkeeper---sounds like we need a retirement RC party--you can bring the shrimp cocktails

oh yeah--the post-----
sounds worth it to clean it all up and to use it if it was a freebie

[m2434]

In college, I worked in a Zebrafish lab. Our, facility manager did a lot of research and even a few experiments and decided that the fluidized bed filters worked quite a bit better than trickle filters. Our lab had two installed, and they did seem to work well, of course they were each something like 4' in diameter and 8' tall...

[capn_hylinur]

Originally posted by m2434
In college, I worked in a Zebrafish lab. Our, facility manager did a lot of research and even a few experiments and decided that the fluidized bed filters worked quite a bit better than trickle filters. Our lab had two installed, and they did seem to work well, of course they were each something like 4' in diameter and 8' tall...

who uses a trickle filter anymore
IMO--most reefers have learned to clean out the filter media and bioballs and run it just as a shell with or without a filter sock

[m2434]

Originally posted by capn_hylinur
who uses a trickle filter anymore
IMO--most reefers have learned to clean out the filter media and bioballs and run it just as a shell with or without a filter sock

Zebrafish are brackish water fish... no live rock there Not making any comments on reef filtration, thats whole other debate...

[capn_hylinur]

Originally posted by m2434
Zebrafish are brackish water fish... no live rock there Not making any comments on reef filtration, thats whole other debate...

I've been looking into this a bit lately---are these zebra fish that are sold as fresh water like the molley.
I was thinking of adding a small school of molleys--but I loved the zebra fish when I was in that part of the hobby--quick moving so they can stay out of trouble.
From what I have been told you have to raise the salt content slowly over 24 hrs to proper acclimate them?

[m2434]

I can't help you there much... they are a model organism for genetic research. We used them to study organization and differentiation of neural progenitor cells. I think we kept them around 15-20ppm, but I think they can tolerate much higher salinity. They don't live really long, but are really easy to breed...

[jamiep]

Well can I bring it back to topic by asking, will a fluidized sand bed pose nitrate problems the same way a wet/dry filter would?

[capn_hylinur]

Originally posted by jamiep
Well can I bring it back to topic by asking, will a fluidized sand bed pose nitrate problems the same way a wet/dry filter would?

Very sorry for hijacking just got carried away.

I am very interested in the answer to your question too

[m2434]

I'd say yes and no... In theory, neither would contribute to nitrates if kept free from dltritus and other waste/debri. With trickle filters there is a tendency for these to accumulate and it is dlfficult to keep them clean - so excess nitrates may accumulate. In theory, the sand particles in a FBF are always colliding and this should help "bump" detrltus out - if using a good prefilter. Also, the flow can simply be reversed to "backwash" the system. So, it should be fairly easy to keep clean and therefore I wouldn't expect as much of a nitrate problem. However , while these properties apply to industrial FBFs, I'm not sure if the same is true for the smaller ones sold in the hobby...

[WaterKeeper]

And here I thought Paul would know all about them as they are somewhat like a RUGF. I guess the main difference is in the degree of bed rise and grain agitation. In Paul's RUGF the flow is slow and bed expansion does not occur. In a true fluidized bed reactor there is high flow and the bed expands and agitates as the flow comes up through it. I'm not sure if it has any true advantage except if one wants to keep the media from harboring a biofilm. In a high agitation bed there is a scrubbing action and any biofilm that forms is kept to a minimum.

A downside is that the water must supply the oxygen and not the atmosphere as occurs in a wet/dry. That means it will lower D.O. if there is biological growth on the media. Such a system will have too high a flow rate for anoxic conditions to form however. That means a separate means of nitrogen export will be needed.

[capn_hylinur]

Originally posted by WaterKeeper
And here I thought Paul would know all about them as they are somewhat like a RUGF. I guess the main difference is in the degree of bed rise and grain agitation. In Paul's RUGF the flow is slow and bed expansion does not occur. In a true fluidized bed reactor there is high flow and the bed expands and agitates as the flow comes up through it. I'm not sure if it has any true advantage except if one wants to keep the media from harboring a biofilm. In a high agitation bed there is a scrubbing action and any biofilm that forms is kept to a minimum.

A downside is that the water must supply the oxygen and not the atmosphere as occurs in a wet/dry. That means it will lower D.O. if there is biological growth on the media. Such a system will have too high a flow rate for anoxic conditions to form however. That means a separate means of nitrogen export will be needed.

I am reading this thread and thinking why not just use a mud/mangrove refugium. At least with this you have a way of removing any nitrates by the magroves.

[m2434]

Well capn, I think that the strongest arument against any supplemental filtraltion is: why bother with something that only helps with nitrification and not denitrification?

[capn_hylinur]

Originally posted by jamiep
Well can I bring it back to topic by asking, will a fluidized sand bed pose nitrate problems the same way a wet/dry filter would?

In the light of what m2434 just posted I would say that both the fsd and the wd filtter has the potential to become sources of nitrates if not taken care of properly and frequently.

[m2434]

Originally posted by capn_hylinur
In the light of what m2434 just posted I would say that both the fsd and the wd filtter has the potential to become sources of nitrates if not taken care of properly and frequently.

True, but to play the devils advocate... so can live rock, live sand and refugiums - if not taken care of and/or setup properly.

[Paul B]

Actually a trickle filter is the best way to remove ammonia and nitrite. (not nitrate) The problem with trickle filters is not that they get dirty, the problem is that they don't get dirty. They stay fully oxygenated which is great. They work so fast that nitrate is produced much faster than live rock can remove it. The best system would be a wet dry with enough rock to de-nitrify. You would need more rock than you could fit in the tank though.
All of the fluidized bed filters I saw were triangle shaped devices with the point down. Water would be introduced at the bottom and the sand would swirl around.
A FBF would have the same problems as a trickle or wet dry filter.
PS there is a retirement party for me in less than 2 weeks.
You coming Waterkeeper?
Paul

[jamiep]

Mikefellows will get a shock when he sees what his simple question has turned into!

Well regards to oxygenation of the water, surely there will be a limit to what will aid the bacteria in the FSB so if we increase it by say venturi or placeing a skimmer before it, there will be a large amount of disolved air in the water anyway. So should the feedwater be oxygenated? Or is air even the limiting factor in the breakdown of wastes?

[capn_hylinur]

Originally posted by Paul B
Actually a trickle filter is the best way to remove ammonia and nitrite. (not nitrate) The problem with trickle filters is not that they get dirty, the problem is that they don't get dirty. They stay fully oxygenated which is great. They work so fast that nitrate is produced much faster than live rock can remove it. The best system would be a wet dry with enough rock to de-nitrify. You would need more rock than you could fit in the tank though.
All of the fluidized bed filters I saw were triangle shaped devices with the point down. Water would be introduced at the bottom and the sand would swirl around.
A FBF would have the same problems as a trickle or wet dry filter.
PS there is a retirement party for me in less than 2 weeks.
You coming Waterkeeper?
Paul

Paul:

I already volunteered him to bring shrimp cocktails

I believe the above situation can still be accomplished by adding live rock to a section of the sump/trickle filter and slowing down the flow of water to give the bacteria in and around the live rock time to work.

[m2434]

Originally posted by Paul B
Actually a trickle filter is the best way to remove ammonia and nitrite. (not nitrate)

I'm not sure I completely agree with this or maybe I'm misunderstanding.

Our facility manager gave us a presentation on this once and from what I remember, the bacteria of a trickle filter works much more efficiently due to oxygenation, however, the surface area of the suspended sand is MUCH greater. The greatly increased surface area more than makes up for the difference in efficiency. So, for example, a two cubic foot trickle filter (with typical plastic bio-balls) may handle say a 55g aquarium, but a 2 cubic foot FBF may handle something bigger, like say 300 gallons.

Originally posted by Paul B
The problem with trickle filters is not that they get dirty, the problem is that they don't get dirty. They stay fully oxygenated which is great. They work so fast that nitrate is produced much faster than live rock can remove it.

I hear this argument all the time, but no one has ever been able to explain the stoichiometry.

X amount of waste -> produces Y amount of ammonia -> Q amount of nitrite -> produces Z amount of nitrate

So, the rate limiting step is waste and ammonia. Therefore, to end up with less nitrate, we need less waste, less ammonia/nitrite or need to convert nitrate to something else like nitrogen gas. It's very possible I'm missing something, but I just don't get how you can convert ammonia “too fast”. What's worse, excess ammonia or excess nitrate?

I wonder if the real issue is that having extra denitrification -> allows people to overstock their tanks more ->
which leads to excess nitrate