Has Anyone Tried a "Rubble Bottom?"

[Mike O'Brien]

In fact, I added detritus to my rubble bottom 10 gallon. The same stuff I siphoned out of my BB sps tank. After a while it made a nice fine sediment that was full of life. That tank was desinged for the growth of pod's and such, and the detritus provided both more pod's and food.

 

[algaeguy]

Awesome!

 

[wrassie86]

Good reading here.I'm planning a move in about 2 months and thought i might try some of the ideas listed here.I have a 125g tank with a DSB now, but after the move i was thinking BB.I really dont like either method as ive been BB before.
But i was thinking about using the rubble rock and a UGF, that would be 4 riser tubes 2 blowing in 2x175gph reverse power heads,2 sucking out with 300gph maxijets.I figured that would make good flow under the rocks and pull any matter that settles.But i'm not sure it would work as i thought UGF's needed a certain amount of smaller gravel on top to create a vacumm or am i wrong on this?

On a side note, i'm not worried about nitrifacation from the rocks or gravel as i have nitrate reductor.But i dont want stuff settling either.

 

[Kent E]

I'm going to attempt this as well. I will have about 40x turn over with sps so fine sand isn't possible or desireable. If this thread is still around I'll post my observations.

 

[barryhc]

<a href=showthread.php?s=&postid=6361194#post6361194 target=_blank>Originally posted</a> by wrassie86
I was thinking about using the rubble rock and a UGF, that would be 4 riser tubes 2 blowing in 2x175gph reverse power heads,2 sucking out with 300gph maxijets.I figured that would make good flow under the rocks and pull any matter that settles.But i'm not sure it would work as i thought UGF's needed a certain amount of smaller gravel on top to create a vacumm or am i wrong on this?

On a side note, i'm not worried about nitrifacation from the rocks or gravel as i have nitrate reductor.But i dont want stuff settling either.

The system that you outline is set-up more like a "void space" sweeper, than a RUGF. This would be accurate, if you had the same flow "in" as "out". Your proposed set-up has 350 GPH "in", and 600 GPH "out". The net effect of this is that 250 GPH must be sucked through the substrate, to accomodate the "imbalance".

This makes it function more like a std. UGF which collects food and poop, with a suction "into" the substrate.

It might be more appropriate, to set-up for RUGF, and add a seperate "closed loop" to the "under plate" area, and through a canister filter, for occasional "sweeping".

This is a method that has been mentioned previously as a possibility, but I don't know of anyone who has tried it, to report on results. It makes sense to me.

I hope this is helpful. > barryhc

 

[barryhc]

<a href=showthread.php?s=&postid=6362281#post6362281 target=_blank>Originally posted</a> by Kent E
I'm going to attempt this as well. I will have about 40x turn over with sps so fine sand isn't possible or desireable. If this thread is still around I'll post my observations.

BB, DSB, Rubble, you name it, they are all fine when operated appropriately. I have to point out however, that I have an 1 1/2" deep 1-2mm layer of gravel over a 3" deep layer of oolitic sand in my tank, and I have tested flow up to 60 X with no problem whatsoever with "sand blowing", so I still fail to understand this supposed discrepancy between "flow" and DSB".

It just isn't so.

> barryhc

 

[Kent E]

Barry,
Are you purposely blowing the bottom of the tank? I will be.

 

[barryhc]

<a href=showthread.php?s=&postid=6364317#post6364317 target=_blank>Originally posted</a> by Kent E
Barry,
Are you purposely blowing the bottom of the tank? I will be.

No I am not. There are a thousand ways to skin a cat. If you are running BB, then "blowing" water at the bottom of the tank can be conducive to eliminating "pockets of detritus".

As has been pointed out however, most recently in this thread, not all "detritus" is the villian that it is sometimes made out to be.

The vast majority of the detritus that is immediately problematic in reef systems, is the organic type, which is made up mostly of fish poop, uneaten food, and "sloughing" of some animal tissue.

This is the detritus that needs to be removed right away, and is done so quite well with skimming and or mechanical filtration.

This material is very many times more bouyant than "mineral detritus", and is easy to keep up in the water column, without having to "blow" directly across the bottom. Many people are obsessing unreasonably IMO, about mineral detritus, not distinguishing between the two types. They think that if they see "anything" on the glass bottom, they are "in trouble".

There is a scheme for water flow, that sends most all of the flow across the top of the water, and is then dispersed down the front glass, and then across the "bottom". From there, of course, "up" to the overflow. There is high flow "across the bottom", but it is not "direct flow", as in "immediately from" a powerhead, or outlet, or spraybar.

Bomber is the king of Bare Bottom, and he uses exactly this kind of flow in his main tank. I have DSB, and have the same type of dispersed flow. It works very well for both of us.

I hope this is helpful. > barryhc

 

[barryhc]

Wrassie86, you might want to set-up your flow just the opposite, with 600 GPH "in", and 350 GPH "out", which will cause a forced upwelling, of about 250 GPH, while still doing come continuous flushing of the void space under the UGF panels. Penguin has larger 300 gph units that adapt just as well, to the "reverse" adapter. I have one on my 10 gal. freshwater, by the way, and the flow is "undetectable" unless you "add air" to the flow.

I have this on the ten gallon tank, with the opposite "up tube" as an "outflow", and NOTHING comes out of the upflow riser tube. There is no other "flow" in the tank.

This is with a 1 1/2" depth of "free-flowing" 4-6mm river gravel. The resulting "general flow in the tank is "UNDETECTABLE"!!

Isn't that interesting? Some experimentation is probably in order, check with Paul B.

> barryhc

 

[Kent E]

Thanks Barry for clarifying. I'm going the other route. I want to have a substrait but also blast it so I'm going for rubble fir that simple reason.

 

[sradmin]

I am following this thread closely because it has particular relevance for me. I about to tear down and restart my 54 gallon corner tank, just as soon as I make other tank arrangements for my Pearly Jawfish. He's getting a species tank of his own. I have been weighing my options, and have cosidered an number of different set-ups for my reef: BB, DSB with plenum wasting, and a "false bottom" with rubble covering and partial sand front.

I am heaviliy leaning toward using the false bottom idea. I want to cut a piece of eggcrate to fit the bottom of the tank, leaving it 4-5 inches short of the very front pane of glass. I'll explain why in just a second... The eggcrate will be sitting on top of 1 1/2 or 2 inch pvc risers. On top of the eggcrate will go the live rock, with any remaining visible part of the eggcrate loosely covered with rubble. Underneath the eggcrate, and plumbed up through the back of it will be a very simple pvc manifold consisting of just enough pipe to accomodate and evenly disperse the mad flow I intend to inject into this area. Forcing water through the manifold and into the false bottom leaves the water nowhere to go but up, so organic materials shed by the rock should remain suspended in the water column where they can be sent to the skimmer for removal.

I want to cut the eggcrate short of the front pane of glass so I can create a wall with a piece of acrylic (or something similar). The acrylic will be bonded to the eggcrate, which will be cut to match the front pane of glass (curved)- creating a space of several inches between the front glass and the acrylic wall behind it. What I want to do is fill this area with sand. Doing so will effectively hide the eggcrate from the viewing front, and possibly provide a home for a variety life. It may also offer some de-nitrifying ability as well, provided the appropriate grain size substrate is used, but I am not counting on this because of the lack of area- the sand portion will have a small footprint. Other than hiding the front of the false bottom, I really don't care if there are any additional benefits to having the sand in the display. Since there will be nothing on top of the sand, it should be easy enough to keep it clean with proper flow, and even if it does fill up with organic material to the point of being a problem, it should be easy enough to siphon out without disrupting the rest of the tank.

I have not yet worked out details such as flow rate or manifold design, but I would surely welcome any suggestions or comments. I'm mostly just thinking out loud right now...

 

[wrassie86]

<a href=showthread.php?s=&postid=6364952#post6364952 target=_blank>Originally posted</a> by barryhc
Wrassie86, you might want to set-up your flow just the opposite, with 600 GPH "in", and 350 GPH "out", which will cause a forced upwelling, of about 250 GPH, while still doing come continuous flushing of the void space under the UGF panels. Penguin has larger 300 gph units that adapt just as well, to the "reverse" adapter. I have one on my 10 gal. freshwater, by the way, and the flow is "undetectable" unless you "add air" to the flow.

I have this on the ten gallon tank, with the opposite "up tube" as an "outflow", and NOTHING comes out of the upflow riser tube. There is no other "flow" in the tank.

This is with a 1 1/2" depth of "free-flowing" 4-6mm river gravel. The resulting "general flow in the tank is "UNDETECTABLE"!!

Isn't that interesting? Some experimentation is probably in order, check with Paul B.

> barryhc

That sounds better,but what i cant wrap my brain around is even with the RUGF and just a rubble bottom.with a bigger tank, i just dont see that items that settle will be flushed out.and more so with out a layer of crushed coral.RUGF work on pressure and UGF work on vaccum.with out some kind of layer to even out the flow in or out i'm just not so sure it would work.

 

[Don424]

<a href=showthread.php?s=&postid=6361194#post6361194 target=_blank>Originally posted</a> by wrassie86
Good reading here.I'm planning a move in about 2 months and thought i might try some of the ideas listed here.I have a 125g tank with a DSB now, but after the move i was thinking BB.I really dont like either method as ive been BB before.
But i was thinking about using the rubble rock and a UGF, that would be 4 riser tubes 2 blowing in 2x175gph reverse power heads,2 sucking out with 300gph maxijets.I figured that would make good flow under the rocks and pull any matter that settles.But i'm not sure it would work as i thought UGF's needed a certain amount of smaller gravel on top to create a vacumm or am i wrong on this?

On a side note, i'm not worried about nitrifacation from the rocks or gravel as i have nitrate reductor.But i dont want stuff settling either.

Wrassie86,

No need to do the pulldown with the other 2 powerheads. All the powerheads should be reverse flow only. For a 125G 4x175 should be ok. I also suggest that you don't earmark your skimmer for mechanical filtration. Use an HOB or canister for MECHANICAL only. If you do a canister, do a spray bar across the back pointed to the front....................nice top down & up the rear of the tank circulation occurs.

I just removed a DSB in my 75G and I'm doing RUGF with a 1" CC bottom for a FOWLR. I'm getting great flow from underneath. If the CC doesn't work out, I'm going for the rubble. It's a great idea and concept. Good luck

 

[Brent Hutchings]

I have been thinking about a rubble bottom as well. I am in the planning stage of a 150 (60x24x24). I am considering using an under- gravel filter plate(s) and running the main return through them in a reverse flow. This would keep any detritus in suspention. I am furthur considering diverting some of the flow from a closed loop, through an ocean motions 4 way, to the under gravel plate as well to give a surge effect and reduce or eliminate dead spots. Could this be the potential middle ground in the BB/SB wars? ;-)

 

[barryhc]

<a href=showthread.php?s=&postid=6366205#post6366205 target=_blank>Originally posted</a> by sradmin
I have not yet worked out details such as flow rate or manifold design, but I would surely welcome any suggestions or comments. I'm mostly just thinking out loud right now...

Steve, this is an interesting idea. you might want to consider how much "area" you want to allow for the front "sand wall". Many very interesting creatures would love to be "displayed" here, and need the sand to do well or survive in the tank. Open brain, slipper coral, tongue coral, fungia, etc. etc. It would be a great specialized " front display area".

Maybe "6" wide. you could use large wide slots at the base of your acrylic wall, some 6mm screen, a couple of thin graded layers of gravel, tapered to "almost nothing" at the front, and then "sand". The slots and gravel ( being adjacent to your high flow ), would give enough oxygenation that Hydrogen sulfide could never occur. Add a dozen Nassarius snails, and a tiger "cuke", and you would never have to do any maintanence to the sand at all, and not worry about it either.

Just a thought. > barryhc

 

[barryhc]

<a href=showthread.php?s=&postid=6366542#post6366542 target=_blank>Originally posted</a> by wrassie86
That sounds better,but what i cant wrap my brain around is even with the RUGF and just a rubble bottom.with a bigger tank, i just dont see that items that settle will be flushed out.and more so with out a layer of crushed coral.RUGF work on pressure and UGF work on vaccum.with out some kind of layer to even out the flow in or out i'm just not so sure it would work.

The "panels" that come with a std. UGF, will actually even out the flow quite well, even with no more than just rubble. There are Diy ways to accomplish this as well. You can incorprorate some finer substrate, under the rubble, if you want, as well, for denitrification, but it isn't needed to "balance" the flow.

My only problem with std. UGF panels for this type of application, is the "riser tubes" and the way that they connect to the panels. I like PVC better than the thin acrylic, and it is easier to "plumb". Some conversion could be made to the panels without too much difficulty.

The animals that you intend to keep really play a large role in the kind of substrate scheme that will work best for you. Can you tell us a bit about the animals that you want to keep?

> barryhc

 

[barryhc]

<a href=showthread.php?s=&postid=6367595#post6367595 target=_blank>Originally posted</a> by Brent Hutchings
I have been thinking about a rubble bottom as well. I am in the planning stage of a 150 (60x24x24). I am considering using an under- gravel filter plate(s) and running the main return through them in a reverse flow. This would keep any detritus in suspention. I am furthur considering diverting some of the flow from a closed loop, through an ocean motions 4 way, to the under gravel plate as well to give a surge effect and reduce or eliminate dead spots. Could this be the potential middle ground in the BB/SB wars? ;-)

I really like the "RUGF-Surge" idea, I wonder if a "dimmer" could be used on "Paul's 4-way" to modify the "cycle interval"?

Maybe only 2 or 3 out of 4 or 5 available "zones", so that "pods" could "remain" in the others. Say it was two out of four, and the
remaining two offered opposing turbulence, in the water column.

> barryhc

 

[Paul B]

I know something about UGF plates and I would not use a RUGF in any manner for any time without a seive, strainer, filter or sponge on the intake. I know it has to be cleaned and it is a pain but it is a necessary evil. I do not backwash or blow any water under my RUGF. The last time I removed the UG plates was for the 25 year cleaning. It was really not that bad. If I really want to I could do water changes by siphoning water up the downflow tubes. I can look under my tank at the UG filter plates and there is nothing in there but I do use a sponge filter on the inlet to the manifold that feeds the thing. I only pump about 50GPH down each tube. I could buy a bigger pump but that would defeat "my" use of a RUGF. I don't want much flow because I do want dome denitrification. I understand, many of you guys are looking to keep detritus suspended. I do not think that will work but thats just my opinion.
Paul

 

[Whaledriver]

Just to review what I thought this thread was about.

Rubble bottom with large rubble NOT sand or gravel.
High flow to keep crap in suspension with no low flow areas.
The use of a undergravel plate to help waterflow only.

Dont be fooled into thinking that a undergravel filter is actually holding gravel.

The design of a system like this is to foster growth of microfauna and help feed hard to keep fish. ie copapods and mysis schrimp for a Manderin or Buterfly fish

 

[~ChrisB~]

Just an update from my tank.


It has been 5 months, and I decided to move the rubble a bit to see about accumulation beneath the rubble bed.

There is none. I am very happy about this.

I have my system set up so that all of the LR is suspended about 1-2inches above the bottom of the tank, and the rubble is about 2 inches deep. I used fairly large pieces, about the size of golf balls.

Water flow is provided by one AM3K and 2 Tunze WB's. My bioload is fairly light for my saize tank, and I skim moderately.

I love the look of rubble compared to BB, and like the fact that there are very few, if any, dead spots in the substrate. This allows many hiding and breeding spots for the fauna in the tank.