Reverse Undergravel Filter? In Refugium?

[cabrego]

I am builidng a barebottom 90g setup. I will also be using a 50 gallon sump with a fuge housing crushed coral, rock, and maybe some macro. I am considering experimenting with running the RUGF in my fuge ~15g fuge section. I figure if it doenst work, it is easy enuff to pull out of the sump.

I would like to open up the discussion to determine the pro's and cons for running the RUGF in this setup.

I would also like to learn more about what to expect from this type of setup to determine if it is indeed working.

[wayne in norway]

Well the pro is it's a very efficient way to filter out ammonia. The con is it's a really good way of creating nitrates. A better question is why do you want to do this?

[cabrego]

Creation of nitrates is an part of the nitrogen cycle. Are you saying the RUGF will trap nitrates?

I was reading Paul B's thread about his 30 year old reef and I believe he stated that it has worked very well for him and has done a great job at homing all kinds of microfauna, pods, etc.

I think the concept is to circulate water flow upward through your substrate to prevent debris from settling in the sand bend.

[Vesa Wuoristo]

I think Wayne was saying that a regular deep sand bed the bottom part becomes low oxygen enviroment and bacteria that remove nitrates likes those conditions. If you add a RUGF in it, there wont be low oxygen areas and no nitrates removed, just produced. Now I don't have experience in using one, but thats the theory. :)

[cabrego]

<a href=showthread.php?s=&postid=13506715#post13506715 target=_blank>Originally posted</a> by Vesa Wuoristo
I think Wayne was saying that a regular deep sand bed the bottom part becomes low oxygen enviroment and bacteria that remove nitrates likes those conditions. If you add a RUGF in it, there wont be low oxygen areas and no nitrates removed, just produced. Now I don't have experience in using one, but thats the theory. :)

I agree with that. I suppose the question is what is the purpose of the RUGF?

Anyone know?

[ludnix]

I imagine it's purpose is that it would provide a huge amount of surface area for aerobic bacteria, similar to a fluidized sand bed filter.

[u418936]

Wouldn't a RUGF hinder caulerpa from getting nutrients from the substrate? I remember from when I was a kid that having an UGF made it difficult to keep freshwater plants.

[IslandCrow]

Well the pro is it's a very efficient way to filter out ammonia. The con is it's a really good way of creating nitrates.

You may be thinking of a wet/dry here. From what I know about RUGFs, it sounds like a great idea for a sump/fuge. Because of the low flow in these areas, they tend to trap a lot of gunk. Keeping a flow through the substrate makes sense to me. I doubt there would be any nutrient deprivation for the caulerpa. There's plenty of "stuff" in the substrate. I know Paul B. is always talking about how much life he has in his, and he attributes it to the RUGF.

I'd suggest asking the expert (Paul B) in this thread: http://www.reefcentral.com/forums/showthread.php?s=&threadid=727454. He seems to be checking it fairly regularly.

[Paul B]

I think if you want to run a RUGF in a fuge it depends on what you want the fuge to do.
I don't think that you should filter all of the water entering the fuge through the UGF or you will be pushing too much water through it causing it to clog with detritus very quickly.
You could use it and only divert some of the water through the gravel after it has been filtered of particles but most of the water should bypass it. If you want to grow algae in there I doubt the UGF will have any impact on it at all. If you want to grow pods and other microfauna then a RUGF would be the way to go with a rather course gravel. The problem with a DSB or any sand bed is that these animals will only live on the surface but a gravel substrait, especially one with some circulation will become saturated with life.
In a fuge, the gravel could be stirred or removed to be cleaned each year or so. This will not hurt the bacteria or the pod population which will be vast. You could even put the gravel in shallow removable trays with mesh boittoms if you like so you could easily remove it to be cleaned of detritus.

[cabrego]

<a href=showthread.php?s=&postid=13508650#post13508650 target=_blank>Originally posted</a> by Paul B
I think if you want to run a RUGF in a fuge it depends on what you want the fuge to do.
I don't think that you should filter all of the water entering the fuge through the UGF or you will be pushing too much water through it causing it to clog with detritus very quickly.
You could use it and only divert some of the water through the gravel after it has been filtered of particles but most of the water should bypass it. If you want to grow algae in there I doubt the UGF will have any impact on it at all. If you want to grow pods and other microfauna then a RUGF would be the way to go with a rather course gravel. The problem with a DSB or any sand bed is that these animals will only live on the surface but a gravel substrait, especially one with some circulation will become saturated with life.
In a fuge, the gravel could be stirred or removed to be cleaned each year or so. This will not hurt the bacteria or the pod population which will be vast. You could even put the gravel in shallow removable trays with mesh boittoms if you like so you could easily remove it to be cleaned of detritus.


Thanks for the reply, I came across the idea after reading your thread.

I am currently building a Bare bottom tank and was considering running a healthy layer of crushed coral primarily for pod production. I am hoping this will let me home a mandarin. I was concerned that pod production could be an issue in a BB tank. After reading your threat about the vast quantities of pods, I naturally wanted to adopt the RUGF concept.

I would also like to keep some macro in the fuge for nutrient export.

Any down side for my particular application??

[Paul B]

Your application sounds fine. I am not sure how many pods will want to leave the crushed coral and float to your BB tank but I would imagine some of them will.