Revival of RUGF including NNR ! !

[wave98]

The Reverse Under Gravel Filter was a great concept about 25 to 30 years ago. Since then it fell out of favor as better reef keeping information was brought to the hobby, and newer technology took it's place. As with the wet/dry, or Bio-Ball systems, the RUGF, was left to antiquity by the "Nitrate Factory" connotation.

And rightly so, for at the time, the substrate was large grained with fairly high flow in many instances, and sure enough the Nitrate was pumped out in volumes, and thus, the RUGF's "demise".

Then came the Berlin system, Turf scrubbers, Skimmers, RO/DI water, Deep Sand Beds, Bare Bottom, Live Rock, Plenums, Araganite, Phos Reactors, and so on. Most of these were looked upon as the new "Magic Bullet", but failed to really fill that elusive goal.

All of these have their Pro's and Con's, but RO/DI and Skimmers look like the biggest winners. Plenty of good results from most of the rest too, although standard Plenums look to be very much on the way out, the way they've been promoted thus far.

So why look back to RUGF after all this time ? Well, I've been one to insist on substrate for the animals that need it, and while DSB's can work quite well, they do have some potential drawbacks regarding maintanence and/or longevity that the RUGF may be able to eliminate or improve upon very significantly.

A bit of consideration is required regarding the plumbing and equipment, and Hypoxic zones within the bed must be established to harbor Faculative bacteria, and conversion of Nitrate.

With that said, the positives are much reduced maintanence, better detritus control, and lowered potential for P "sinking", Hydrogen Sulfide and Heavy Metals build-up. :idea:

So let's take a crack at it folks.

> Barry

 

[Scooterman]

I've been waiting for this one, so let me read it & get back later!

 

[Boomer]

Barrrrrryyy

A bit of consideration is required regarding the plumbing and equipment, and Hypoxic zones within the bed must be established to harbor Faculative bacteria, and conversion of Nitrate.

Why ? Enough LR will do that. Lets look at something else just for shits and giggles A DSB tank with heater cables in the botom. The warm water rises and cold water sinks, so it is never really anoxic. Some places may be oxic

RUGF

Ok, so what do you want to pump all that shit into the gravel bottom via RF, although this better than a std UGF where you suck in unfiltered water ?

 

[Krish]

Sounds great Barry! After I do a little assigned homework , I may be able to contribute a bit here.

 

[Scooterman]

Before discussing the RFUG it may be a good idea to explain the design of it first, starting with relation the UGF & plenum. I see nothing wrong with people wanting a sb for their creatures, they deserve that I'm sure, I think reasons for changing system designs isn't necessary failure in any of them rather the desire to keep different reef tanks, each have different requirements & you can't do them all in a glass box & expect to thrive everything you throw in. Each success is dependent of several things, mainly what are your goals or idea of a reef, what do you want & how much do you want to be reliable for. I had success for years with a UGF using air to cause water circulation, sucking water down through the substrate into the UGF. This method worked fine until it became full, then I had to tear it down & clean it, lots of work but well worth it.Later I installed a ph sucking water through, this seemed to work even better but eventually I had the same problem but stuck with it for over 25 years before migrating to sw.

 

[spongebob lover]

i still know very little about this UGF, but i'll be tagging along so can learn more about it from the experts .

 

[ethanriley]

Boomer:

Three questions:

1) Are we talking about hypoxic or anoxic zones? (There is a difference?):doubt:
2) What in your opinion would assist the nitrogen fixing bacteria within these zones (hypoxic or anoxic depending on which you say is correct I am not sure)?
3) If we supplement molbedeyum to assist these nitrogen fixing bacteria should we not increase the percentages of molbedyum to higher concentrations than normally found in natural saltwater? Again this assumes why we supplement molbedeyum.

Assuming that is why we would want to pump the nutrients through the sand bed.

 

[ethanriley]

Another question:

If we warm the DSB on top of the reverse flow UGF and increase supplmentation of molbedeyum ( I am not sure the concentrations so don't ask LOL)could we not pass the nitrogenous waste through the DSB filter and then through the war water cold water affect transfer it back into solution to be removed through water changes?

 

[ethanriley]

Mis read part of what you said you were referring to hypoxia with the cable warmers. So that raises another question do we not want some anoxic zones or are they too dangerous in our closed systems that you end up with fish and sessile animal kills? Just trying to understand.

 

[Paul B]

I am fairly sure that I am running the longest RUGF here, maybe in the country. I run it wery slow, 50gph down each tube with a sponge filter on the powerheads. I cleaned it once in the past 25 years. It was not really that dirty either. My nitrates are zero. The only maintenance I do on it is to clean the sponge about once a week and twice a year I stir up the dolomite substrate with a diatom filter. If you run the system fast you will push a lot of detritus under the gravel and you will also never have any anerobic bacteria but with a very slow flow I think that in time there will be some areas of anerobic bacteria between the grains of gravel where detritus will settle. I have been running my reef continousely this way since 1972 with never a crash.
Paul

 

[wave98]

Heater cables, :lol: :lol: :lol:

Sorry Boomer, I forgot to include Filter floss, Diatom filters, PolyPads, Filter Socks, and Carbon. Of course, the incoming water has to be filtered before going through the RUGF. Another Nitrate Facrory, Oh my God ! ! !

And I hate having to repeat myself, but: So why look back to RUGF after all this time ? Well, I've been one to insist on substrate for the animals that need it, and while DSB's can work quite well, they do have some potential drawbacks regarding maintanence and/or longevity that the RUGF may be able to eliminate or improve upon very significantly.

So while the Bare Bottom crowd may be happy with their setups, people who require substrate for whatever reason don't have that choice, and substrate it is, so "how best to go about it" ? RUGF, I presume !

Three questions:

1) Are we talking about hypoxic or anoxic zones? (There is a difference?):doubt:
2) What in your opinion would assist the nitrogen fixing bacteria within these zones (hypoxic or anoxic depending on which you say is correct I am not sure)?
3) If we supplement molbedeyum to assist these nitrogen fixing bacteria should we not increase the percentages of molbedyum to higher concentrations than normally found in natural saltwater? Again this assumes why we supplement molbedeyum.

1) Actually we are talking about both. It is quite difficult to have a Hypoxic ( low oxygen ) zone, without an Anoxic Zone next to it.

2) Nitrate and Anaerobic bacteria.

3) Molybdenum supplements ? Is anyone supplementing Molybdenum ?

Thanks > Barry

 

[Boomer]

Three questions:

1) Are we talking about hypoxic or anoxic zones? (There is a difference?):doubt:

Yes there is, hypoxic is lack of O2, it doe not mean NO O2. Anoxic means NO O2

2) What in your opinion would assist the nitrogen fixing bacteria within these zones (hypoxic or anoxic depending on which you say is correct I am not sure)?

They do not need any help they do well all by themselvies

3) If we supplement molbedeyum to assist these nitrogen fixing bacteria should we not increase the percentages of molbedyum to higher concentrations than normally found in natural saltwater? Again this assumes why we supplement molbedeyum.

Moly is not needed as a sup. and has never been shown to have a need as a sup. Reef tanks have done qutie well with out it. There is enough going in there by other means. And what or how are you going to test for it.


If we warm the DSB on top of the reverse flow UGF

You misread that. There is no RUGF, just heater cables in the DSB. Planted aqauriums often run this way, it stops the bottom from becoming anoxic, although most areas will be hypoxic some wll also be oxic. If the bottom has a very slight circulation, which cables do, there is no anoxic conditions." ___If there is to much water movement the water will get oxic. So you need to control the temp between the bottom and the tank within a 1-2 degrees___."

So that raises another question do we not want some anoxic zones or are they too dangerous in our closed systems

No, you do not want anoxic zones, you want Facualtive (hypoxic)Anaerobic Zones and not Obligated ( anoxic) Anaerobic Zones. Anaerobic Bacteria can be either Obligated ( must have no O2) or Facultative ( with or without O2 but preferr to be with a tad of O2. They can live either way). You also have Facultative Aerobic and Obligated Aerobic.

 

[Boomer]

Sorry Boomer, I forgot to include Filter floss, Diatom filters, PolyPads, Filter Socks, and Carbon. Of course, the incoming water has to be filtered before going through the RUGF. Another Nitrate Facrory,

Ok, now that that is cleared up I did this for 20 years and as Paul pointed out they need to run at a slow rate. Way to many people run them like the water has a turbo charger behind it. Only one company ever made a proper RUGF, Ehiem

Heater cables :lol: :lol:

What is this so funny, maybe you can explain it to me ? Heater cables do not have to go in the tank they can go under the tank :shock:

 

[Paul B]

It seems that almost all people that post to these sites and virtually all the people that E mail me think you should run a RUGF as fast as you can to keep detritus in suspension. That would never work unless you were running a fire pump and the gravel was also in suspension. Also the slower you run these and the better the seive or pre filter you have, the longer it will run without problems. With a properly run RUGF you also get an unbelievable amount of fauna living all throughout the gravel. When I lifter my UG plates out two years ago for the 25 year cleaning the gravel was full of tiny tube worms which also make excellent filters.
I ran all three of my downdraft tubes together and terminated them into a small plastic container that sits above the water. This way I onlu need one powerhead and one sponge to power the entire thing and all tubes get the same volume.
The green thing is the container where the three tubes connect.

Paul

 

[wave98]

What is so funny, maybe you can explain it ? Heater cables do not have to go in the tank they can go under the tank :shock:

What cold water, and where does it "sink" to ?

> Barry

 

[wrightme43]

I think and I may be wrong that it is the water that is flowing in to replace the water that is marginally less dense from being in contact with the heater cable.

 

[Boomer]

Oh come on now :lol:The water heated right at the cables will be warmer than the surronding water. That warm water will rise, be replaced by cooler water/less warm, which will take its palce. Why sink, cooler water is more dense, it has to sink. Planted FW tanks have run this way for 3 decades

Well, I see wright is awake today

 

[wave98]

Convection currents.

Bomber:
The warm water rises and cold water sinks, so it is never really hypoxic.


If it isn't Hypoxic, it doesn't suit the application. Do you mean never really Anoxic ?

> Barry

 

[ethanriley]

Ok I am interested in the concept now let me see it. As I understand so far you have an under gravel filter which you place on the bottom glass of the tank. Generally there are two lift tubes per section. To one (all) of these tubes you attach a small powerhead, subermisable pump whatever which pushs flow back down the tube(s) at a slow rate per Paul's prescription which is probably the most long term example we have. Am I missing anything? This in turn forces water slowly through the substrate providing a hypoxic environment for faculative bacteria and assists in preventing anoxic regions which may be associated with DSB's. Did I miss anything?

 

[Paul B]

The only thing incorrect is that the water being pushed under the gravel does
not provide a hypoxic envirnment. The hypoxide envirnment, if it happens at all, is from the slight clogging that will happen in a few weeks from detritus. The hypoxic areas will be the tiny spaces where the gravel is touching and increases slightly with detritus. If there was a clear passage of water through the gravel there would be no hypoxic areas. A reverse UG filter by design will never support the same amount of anerobic bacteria as a DSB but IMO it will operate longer, have less maintenance, is more stable, supports more fauna and has less chance of crashing. When I clean mine by powerwashing with a diatom filter it becomes renewed and can go another six months with virtually no maintenance. When a DSB becomes clogged, what do you do?
Paul