Has Anyone Tried a "Rubble Bottom?"

[Whaledriver]

Chicago I think that will work with the denitrator but without it, it would fail. I wonder if you are going to vacuum your gravel?

I think anything under 1/2 inch is gravel and detritus and silt will build up over time. I think the minimum size of the rubble is relative to the size of the pods and mysis. It will also become a nitrate factory. Chicago has a way to deal with the nitrate. I just hope people don't try that and become a tank from the 80's with all the problems of a under-gravel filter. I would hope that the concept of the life in the rubble is not forgotten since I think it is the best reason for a rubble bottom

 

[Chicago]

purely astetics in the tank.. and ease of cleaning.. i have a large sump 300 gallons in the basment with phlenum. it is the biological filter and does quite well at kepping the nitrates at zero.

what i was looking for was to just cover the bottom of the tank. i have never had this size grave. in the 90s in my old tank i was using the speacial reee grade with plenum and that worked well.. that is why i am using it in the sump in the basement...

i liked the look of the sugar so went for it in my tank..but that stuff is to fine in my opionio for a reef sps dominated tank.. cloud storms ect.

what i did notice about the sugar size is that it accumulated detritus the same .. just more fine like. ... sand goes greyish looking.. (not to be confused with black which is signs of sulphur).

i am hoping that this size wil be good for pods.... anyone use this size in their tank?

pros and cons?

i dont think it will be nitrate factory as i am not using a large depth...

i would have gone bare bottom perhaps but needed something to support the reef structure ...

if i had it all to start over i would have done some precasting with rock on the bottom glass... that way not dependant on the sand to support the structure of the reef rock

 

[Whaledriver]

I have never thought of precast on the bottom. I have seen it on the walls and it looked good. For a high flow sps tank that would look cool and very natural.

 

[ultraxr]

Hi folks. I am finally done with reading all 16 pages of this thread. I'm in the process of taking down my tank and redoing it. I'll be parting out a good chuck of my LR too for that i have way too much that its making my 120 cramped up and looking like a 55 gal tank.

I transferred my livestock and few pieces of corals into my old 55 gal tank. I have it set up as a prop tank. I've been slowly picking up live rock rubble and tossing them into my prop tank. I plan on going 100% rubble bottom pieces ranging from 1"- 4". Mainly tonga and fiji branch rubble. I'm also waiting for my custom sump to be built. So in the meantime, I'm getting my read on and absorbing as much as i can through your guy's experiences.

Finally, no more just imagining and wishing... time to dive in and get the ball rolling to get this set up.

 

[miatawnt2b]

Good luck.
The previous owner of my tank decided to make a faux epoxy sandbed for the bottom of the tank, so I decided to rubble the entire thing with 1-2" rubble. Been set up now for 2 months, and I really like not having to worry about sandstorms with monster stream flow. My pistol shrimp found a nice crevise under a rock and seems happy as a clam... no... well... pistol shrimp.

-J

 

[Whaledriver]

I have had my 30 gallon set up with a under gravel filter plate. I put the rubble on top and things seem to be going well after 3 months. I have 2 reverse flow under gravel filter pumps circulating water under the plate. All seems to be fine but I would like some more flow to keep silt from building up in half of the bottom glass. I also have a cpr hang on algae filter and a hang on Prism skimmer. Pods and mysis are really starting to take over as well as the 2 types of snails. The only other thing in the tank is a large brittle star.

The review of my setup would say it would be a good tank for a small fish that likes to eat pods. I would think and food the fish wont eat would be eaten by the pods. I doubt that the pods population could be decimated by one fish as long as the rubble is about 4 inches deep (golf ball size)

 

[snadaud]

Nice thread !

I've had my tank set up with large gravel/small rubble (4-6"deep) and RUGF powered by a canister filter also filled with the same substrate for over 3 years and am very happy with it
It really is teeming with life : pods, worms, brittle stars, etc...
The reasoning (or should I say wishful thinking ? ) why I put a canister filter to power it was that the water sent under the plate would already be depleted in O2 which in turn would help with some denitificationg in the substrate while not allowing for development of anaerobic conditions and production of H2S.
My chiller is also on the same line, so that the water injected under the plate is cooler.

One thing I haven't tried yet but will do on my next tank, is put some air diffusers under the plate and switch then on for a few minutes at night with a timer to put some of the animals living in the substrate in suspension so that they can be fed upon.
Another option I am considering to achieve that is to put a PH with a venturi on a T I could install on the line sending water from the canister filter to under the plate, and run that on a timer to send a sudden extra flux of water + bubbles under the plate.

The ONLY reason I want to do that is to put some critters/bact, etc... in the water column for filter feeder and corals to feed on. We might even be able to hope to keep some aposymbiotic animals if the bed is thick and old enough...Well one can always hope...

I do have 0.5 to 1" of silt at the bottom of my bed but I'm not concerned about it since the worms tunnel in it and I think it might actually provide an habitat for smaller pods than the gravel.
Just my 0.2$

 

[Whaledriver]

snadaud
I don't think you have a rubble bottom. I think that if you have that much silt building up and are worried about anaerobic conditions then you have a fundamentally different system. I also would not put air under the filter plate since this will lead to bubbles that block the water flow and create dead spots. If ph and oxygen is a problem under the plate you should rethink the size of your rubble and flow rates.

I think you need to have enough flow to remove silt . That, is as I have found out, a lot of flow! I am guessing about 15x turnover going under the plate. A help might be a SWID device and a power head.

As for the silt being a habitat you might be right but is that the habitat that you want in a rubble bottom tank? I think that good rubble with lots of nooks and cranny's if best for the flow needed.

 

[just dave]

Here is one.

 

[snadaud]

Hi Whale,

You're right about my substrate, it is medium to large pieces of crushed gravel 1-2" so it isn't exactly rubble. However some of the tank pics I saw in the thread seemd to have similar substrate.

I sometimes acidentally inject air under the plate when I forget to switch the canister filter off while doing a water change. The bubbles are not trapped under the gravel but come through it quickly, bringing along some surprised pods.

The reason I'm considering doing this intentionally has nothing to do with the ph or oxygen level under the plate, it is only to put some critters in the water columns. A bit like Peter Wilkens stirring up his sand.

As for the silt I don't want to get rid of it ! Matter of fact is I love it... I consider it like a breedinmg ground for small pods...sort of an in-tank undergravel refugium
:rollface:

 

[cwschoon]

What a thread! I have been BB since my move but am going back to 1-2" of CC and rubble. BB just seems unnatural and I think the critters that inhabit sand and rubble are necessary. What is a good combination of ditritus maintenace creatures? Specifically, which hermits/snails/stars for the shallow sand and rubble?
Thanks.

 

[Whaledriver]

I think the best way to run a rubble bottom is without the CC since it will end up causing problems over the long run. It collects detritus that can raise nitrates.

I would do about 4 inches of golf ball sized rubble with lots of nooks and crannies in them. Below that I would use a under gravel filter plate and run about 20x turnover through a closed loop or power head. Some type of SWID or pulsing water would also help a lot.

This seems like a lot of flow but it doesn't bother the critters at all. Remember this recreates a natural rubble habitat. I also like the way food floats all around til something grabs it and eats it.

One other thing that I think is important is a algae filter or a lot of water changes. I prefer a algae filter like a cpr refuge with just cheato

 

[cwschoon]

I agree with you whaledriver but I am going to put a bit in. Will not cover the entire tank bottom with cc. Am not going to cover the entire bottom with rubble either. I just want the biodiversity back; need pods for a mandarin. Which crabs/snails would you advise? I have my opinion but am always interested in what others have to say. I will do a 5 gal siphon/water change one every one or two weeks.
Thanks.

 

[algaeguy]

Been a while since I chimed in on the topic, so I thought I'd add some more feedback!

I am a big fan of using the rubble on a completely bare bottom, if for no other reason than you can blast flow around without stirring sand up all over the place. However, I think that cwschoon's idea of adding some CC to the rubble mix is not too problematic if good overall husbandry is used.

I've tried incorporating a rubble zone area in my new seagrass biotope system...The rubble is located over the thinnest (about 1.5-2 inch) part of the sandbed, up front where I can easily access it for maintenance.

I thought that it would be a bit of a challenge to have rubble over sand, but this has not been the case to date...My wrasses, Centropyge multicolor, and Ctenochaetus Tang spend a lot of time foraging in this particular area, so I still maintain that with good hasbandry and a proper mix of animals, you can potentially run a rubble zone over sand as well.

As many people have pointed out to me, the fear that we have about excessive detritus might be grounded in some outdated thinking. If we realize that some detritus (or perhaps, materials within the detritus) form the basis of food webs for some animals, we can learn to live with some of it!

In all seriousness, of course, the ideas on this thread have been fantastic, and I'm stoked to see so many people trying different approaches to reef systems!

Keep the ideas flowing!

Scott

 

[RichConley]

<a href=showthread.php?s=&postid=6712799#post6712799 target=_blank>Originally posted</a> by barryhc
Good thoughts Brian. Consider putting two outlets from either 2 pumps that alternate by timers etc. , or 2 outlets from an OceansMotion valve that extend under the egg crate with "90's", and point not quite at each other from opposite ends of your under crate space.
This will give you an upwelling wave action, and a fairly well cleaned bottom space as well. The wave action will be adequate for most of your animals ( maybe 2/3 ), and make the remaining more specialized flow requirements for certain animals easier to accomplish.

> Barry

Barry, I was thinking of doing something similar. Maybe 120g, and basically put eggcrate down about 3" off the bottom. Put a maximod at each end, but do it by cutting a hole in the eggcrate, and having the maximod facing straight down, basically using the eggcrate as a bracket to hold the mjmod.. I think it would keep the bottom of the tank clean, and the egg crate would act as a diffuser. You'd have a ton of water flow, but it would be very light, and defuse. Water upflowing through eggcrate and rubble would have some particulate in it, so filter feeders, etc, in the rubble area should do well, but it would keep anything from accumulating at the bottom.

 

[Whaledriver]

I think the problem with a sandbed and a rubble bottom is the transition between the two. If you set up the tank to move the water towards the sandbed you might have a interesting system. Maybe a surge device that dumps over the rubble and pushes the wave towards the sand bed side of the tank. This needs a long tank so at least a 6 foot tank with a non standard hood and return system.
I am doing my rubble in a 30 gallon tank and trying to keep things under $5 a gallon for the whole setup. Needless to say used equpment helps but things always creep to $10 a gallon in the end. If price and space where unlimited a long tank that recreated the face of the reef from the rubble to the sand bed to the heart of the reef would be one of the most interesting tanks you could create.

 

[LazyReef]

It has been a while since I posted on this thread, but I have removed my rubble in th e 40 and I am running Bare Bottom on both. Since the change I now have a detritus bottom. (I will get around to siphoning and putting down some pretty white sand 1/2 inch)

I think that substrate in the tank, rubble or fine is a phospahte source (eventually) and I will run fine sand on the bottom only for decorative purposes. I siphong off half the sand out, rinse it under tap water and return it clean every three months or so. I use a very caulerpa prolifera packed 30 gallon tank as a scrubber and pod farm.

 

[Whaledriver]

When you have a under gravel plate under the rubble you have a modified bare bottom tank. With the proper water flow no detritus will collect under the rubble. This much water flow would also make it a good bottom for a sps tank. With luck you should even have natural frags created on the rubble as frags fall off.

This idea makes the concept of a rubble bottom visually attractive. The other benefits are the life the rubble supports.

 

[RichConley]

<a href=showthread.php?s=&postid=8678035#post8678035 target=_blank>Originally posted</a> by LazyReef

I think that substrate in the tank, rubble or fine is a phospahte source (eventually)

Only with poor husbandry.

 

[Whaledriver]

I have been looking at my set up and thought of a new option. I could use my under gravel filter fittings and run a closed loop of water just under the filter plate. This would let me hide the pump under a rock and eliminate the tubes that come out of the filterplate on my existing setup. I currently use reverse flow UGF pumps that are not the nicest things to look at. Since there is so much water flow under the plate detritus wont build up. I also don't think there will be a problem of water becoming anoxic since there are so many holes in the plate water will naturally mix.

The end result of a closed loop under gravel filter setup will be a very uncluttered tank with high flow where it is needed to keep detritus from building up. The side benefits are eliminating a unsightly glass bottom and creating a heaven for pod like critters.
This would also be a nice SPS bottom since coral frags would form naturally on the bottom rubble.