Duplex sump concept

[ooba]

Great thread, has helped a lot in not only planning my sump and refugium, but also in spawning more interest as i just bought and read Steve Tyree's book. And i will need to read it a second time.
A question, i think from the ease of maintenance, going barebottomed in the refugium zone of the sump would be the way to go, but would some of the organisms we are trying to cultivate (worms) thrive more easily in a sand bed, be it shallow or deep?
and second, just to clarify, you suggest tossing any 'bad guy' inverts into the refugium zone...is there any concern for these inverts preying on the sponges, tunicates, worms and other animals we are cultivating?
Thank you

[mr.wilson]

There appears to be ample shelter for worms in the duplex filter without the need for sand. They can move freely through the macro-algae, rock rubble substrate, and eggcrate structure. They have easy access to detritus in each of these zones, and the loose rubble is easier to navigate than sand.

I find that bristle worms prefer to live within the macro-algae, or perhaps they're just easier to spot there. Detritus is more abundant in the open areas than within the sand bed itself.

A deep sand bed would be a great addition to the duplex method, but it requires a deep area to work with. One that is hard to come by for most installations. The main purpose of the duplex method is to fit a lot of function into a small space. The area below a reef tank runs out of real estate quickly once you add plumbing, pumps, sumps, and miscellaneous gear. If you have a large sump room in an adjacent room or basement, then it would be wise to house each zone in its' own dedicated container. More space (depth) could be given to the benthic zone, and deep sand bed. The macro-algae zone could use a larger footprint, but the depth should remain shallow (4-6") for the reasons given earlier. This would be described as a "Naturalized, or Zoned System", rather than a "Duplex System".

The toxic nature of sponges makes them unpalatable to typical bad guy detrivores like starfish and crabs. I haven't noticed them parasitizing tunicates or worms either, but you would have to monitor each inmate closely for a while. They would be easier to remove from the duplex filter than from the display tank.

[snorvich]

What speed of water do you pass through the refugium part? (GPH)

[mr.wilson]

Flow to and from the sump isn't the crux of the system, but cycling 3 x the tank volume is the ideal ratio to aim for.

For some reason, the norm has climbed to 10 x the volume or greater. This causes drainage shortfalls, excess noise, micro-bubble formation and return to display, heat transfer, excess energy consumption, poor surface skimming and inefficient protein skimming.

The function of moving water to the sump is to fulfill the requirements of the protein skimmer and refugium. Most protein skimmers require about 3 x the volume of the tank for throughput, and refugia function better in a low flow environment.

Any flow in excess of the protein skimmers demand is counterproductive.

[snorvich]

Since I will be having a separate refugium, can I flow 3 times the tank volume to the skimmer in the sump and only ONE times the tank volume (325 gallons) to the refugium? Thanks.

[snorvich]

This is what I am planning. Any issues? Will be fed from the sump with an Eheim 1250 (300 gallons per hour). Thanks in advance.

[tasos]

Mr Wilson, which is the flow you would prefer for a 20G duplex refugium, presuming that most of it (aprox.70%) will pass through the macroalgae compartment leaving the rest slowly ''glide'' below to the filter feeder's zone!!
Will a refugium like that back up for a 120G total mixed reef system with live rock, 1-1,5 '' of sand on the display? Do I need to stay with the caulerpa or can I switch to chaetomorpha? I a bit worried about c.racemosa leaking dangerus substancies to the water especially for sps corals...
A note: white hard shelled worms seem to like the aprox. 500g/h flow of my sump, and like to occupie the glass of my skimmer compartment ,where is dark.....most sponges also don't hate enough flow,so why do we have to have relatively slow water flow to the cryptic zone?

[tasos]

Hello, maybe Mr Wilson is out of the forum these days.Anyone else?I want to procede with the project, but I am not convinced that the area within the eggcrate surfaces is bigger than the whole area behind and inside the rock, glass, sand surface in the rest of the aquarium,in order the eggcrate fauna being able to clear polution in the tank!Thank you!

[mr.wilson]

Originally posted by snorvich
Since I will be having a separate refugium, can I flow 3 times the tank volume to the skimmer in the sump and only ONE times the tank volume (325 gallons) to the refugium? Thanks.

By all mean, yes. You can direct the proper amount of floe to each zone as required. It's part of the idea that we are not limited to whatever our pump just happens to produce.

Unfortunately, the purpose of having a sump has slipped away for some. Many reef systems are designed to go through great effort in moving water to and from a sump, while making little effort to process the water in doing so. Useless protein skimmers, ineffective refugia, and misuse of chemical media make some sumps more of a liability than an asset.

I can't say I know the magic number for refugia flow, as it depends on what you're doing.
Sponges and other sessile (stationary) invertebrates need a constant supply of nutrients floating by, and some macro algae need good flow to remove detritus (particularly chaetomorpha and gracilaria). Zooplankton flourish in slow flow.

You also need to asses your detritus collecting practices. If you don't have a good mechanical prefilter, you should have a settling area, where the influent water is slow enough to allow detritus to settle in one, easy to harvest area. This area doubles as an influent zone for your protein skimmer, if you cannot plumb it directly to the display tank drain. The settling point can be cleaned manually or you can employ aiptasia anemones, colonial polyps (anthellia, xenia etc.), starfish, urchins, crabs and snails.

If some of your processed protein skimmer water is bypassing the refugium, make sure you do it with plumbing (add a tee and valve), and not a large glass bypass section. Sump designs that segregate the refugium to a small strip off to one side, decrease refugium efficiency and allow for wasted space.

Providing slow flow to the lower, Benthic zone, portion of the Duplex filter is simple, as the water from the protein skimmer zone will take the path of least resistance, across the top with only passive flow below the eggcrate platform. The relatively large size of the Duplex area creates slow pressure while maintaining high volume. High volume is rarely a problem, while excessive pressure can be problematic.

[mr.wilson]

Originally posted by tasos
Mr Wilson, which is the flow you would prefer for a 20G duplex refugium, presuming that most of it (aprox.70%) will pass through the macroalgae compartment leaving the rest slowly ''glide'' below to the filter feeder's zone!!
Will a refugium like that back up for a 120G total mixed reef system with live rock, 1-1,5 '' of sand on the display? Do I need to stay with the caulerpa or can I switch to chaetomorpha? I a bit worried about c.racemosa leaking dangerus substancies to the water especially for sps corals...
A note: white hard shelled worms seem to like the aprox. 500g/h flow of my sump, and like to occupie the glass of my skimmer compartment ,where is dark.....most sponges also don't hate enough flow,so why do we have to have relatively slow water flow to the cryptic zone?

I like to use the term "benthic zone" rather than "cryptic zone". Steve Tyree's term "cryptic zone" is specifically in reference to slow flow, dark areas on or near the substrate, and in some cases, on the undersides of rocks. The term "benthic zone" encompasses a variety of habitats that can be found in or near the substrates. This allows for some passive illumination and may include some fast moving water.

In the case of an overflow box, it can be deemed a benthic zone, as it isn't directly illuminated, but some light may reach it. The flow rate is clearly rapid in this zone as all of the water going to the sump must pass through a relatively small area. You may even get bubble introduction if your overflow is undersized or poorly designed. Hard tube worms, sponges, and squirts flourish in these areas. It's rich in concentrated nutrients and receives more food (nutrient import) than the display tank in some instances (careless feeding of floating foods).

The idea of having a Duplex filtration system is to provide a variety of environments so there is a suitable home for greater biodiversity. It's a "build it and they will come" approach. Wherever there is an opportunity in the the ecosystem, nature will provide life. Your overflow may be the most opportunistic area, so it will be populated first. The lower benthic zone is also slow to be populated as invertebrates must travel through a series of physical barriers (mechanical filters) in order to reach the zone. It's a good idea to directly seed the benthic zone or at least delete mechanical filtration for the first three months.

The biomass in your benthic zone(s) is an indication of nutrient levels. An overgrown benthic zone is a sign that you have the means to reduce (assimilate and dissimilate) organic compounds, but it's also a sign that you have a high need (high bioload).

You may choose to upgrade your protein skimmer performance, add more chemical media (carbon, polymeric absorption, ion exchange resin etc.), increase mechanical filtration, or increase macroalgae harvesting, if you feel that you have too many free nutrients.

A well established, naturalized system like this will act as a live food (zooplankton) farm for the display tank. At this point of maturity, you will be able to decrease nutrient import (feeding the tank). It will never be a fully self-sustaining ecosystem, but a balance can be achieved that will limit your input.

I wouldn't worry about the C. Racemosa. Chaetomorpha grows too slowly to be an effective exporter in my opinion. Every form of algae has some kind of toxic allelopathic agents. These toxins will not effect the display tank if algae is grown in a healthy environment, free of competition and threat to its' existence, such as over-crowding and interruptions in illumination. Some varieties, such as Caulerpa Prolifera have anti-bacterial agents that may benefit the display tank. Algae, invertebrates, and fish have a symbiotic relationship in nature. A similar balance can be reached in captive reefs.

[snorvich]

Mr.Wilson, did you have a chance to look at the design above? Any issues or problems? Thanks.

[mr.wilson]

Originally posted by snorvich


This is what I am planning. Any issues? Will be fed from the sump with an Eheim 1250 (300 gallons per hour). Thanks in advance.

I assume the water enters on the right and returns to the display tank from the left?

The hole in the upper left corner should be used as an emergency overflow and the drain from the display tank should flow directly into the protein skimmer in the first section (on the left) if the protein skimmer design allows for it.

The dam and weir baffles look a little high and would work better if reversed. They look like they may limit your water overflow capacity. You don't want water to enter or leave the benthic zone via the bottom. You want the water to flow over a partition so bubbles can pop, and the water can travel across the surface, as passive flow. Otherwise, you will have all of the difficulties that come with an undergravel filter, namely trapped detritus.

Your current design will introduce bubbles to the benthic zone at the influent end, and trap detritus at the effluent end. It also allows for splashing and bubble introduction at the left end where the water enters the pump intake, unless your auto top-off system is good, and the water doesn't fall more than an inch as it travels over the glass partition.

You should add two more dams on the inside (Duplex side) of the sump. This will give you a proper bubble trap and water introduction. The water will then travel, over-under-over, instead of your current over-under configuration.

I don't use glass partitions as they limit the amount of water available to the pump, should you have a top-off deficit. I find eggcrate walls are adequate for keeping the macroalgae in check, and the Duplex structure and macroalgae to be enough to pop bubbles.

Keeping it a simple, modular design, allows for ease in improving it as technology and methodology changes. The one area that benefits from a glass partition is the first compartment where the protein skimmer is located, as it assures that incoming water is processed in a first-in-first-out manner. It also segregates settled detritus and aiptasia.

Glass baffles limit your flexibility in adjusting the water level as well. Eggcrate baffles allow you to use the float valve to regulate the operating water level.

Make sure your sump can hold the excess water from the plumbing, protein skimmer, overflow box, back-siphoned water from return line and top 1/2" - 1" of the display tank in the event of power failure. Always test your system with a mock power outage to see what happens (where the water goes) and plan accordingly.

[snorvich]

Mr.Wilson,

Thanks for the comments.

The input to this refugium comes from the chamber in the sump which is post skimmer and returns to the sump just before the pump which returns to the aquarium. This refugium is gravity fed so that if the feed pump stops, everything stops. It is 12 inches above the sump.

I have tested the sump for power outage conditions (which occur when I do water changes) and there is no problem there.

I will add the extra partition so the water goes over-under-over.

Any other comments will be appreciated.

[mark caruana]

Mr. Wilson,
I'd like your opinion regarding my duplex 'fuge. I set it up about 3 months ago and I'm wondering if I should syphon the bottom because of the build up of detritus?
There is an abundance of life, including 'pods of every size, worms and worm tracks through the detritus, mysis shrimp, and tunicates. I feel to syphon would be counter productive. The cheato on the top layer is full of little brittle stars and bristle worms and grows quite well.
I've attached a photo so you can see the build up of detritus.
Any thoughts or suggestions would be greatly appreciated. Thanks

[tasos]

Çello Mr Wilson,
thank you for yor reply, I will keep in touch as I build the system...

Mark, you didn't attached any photos.....I would like to see what you have done....also some macro photos showing the benthic fauna would be great!!!

[tasos]

..

[mark caruana]

Hello Tasos, I was able to submit photos to my gallery but not to the message. (I'm new here) I have some pics that I'll try to submit again.
Thanks for your reply.

[mark caruana]

OK, I've figured it out. Here is my set-up. My skimmer feeds the refugium. As you can see, I have about 4 or 5 inches of rubble over the benthic zone and the cheato on top of the rubble. My nitrates have slowly started creeping down but still around 10 ppm. To syphon would mean removing all the rubble, but I'll do it if I have to.
I have no mechanical filtration and no chemical filtration either.
Any thoughts or suggestions would be greatly appreciated.
Thanks.

[wmfsoll2]

Great thread. I am very interested in incorporating this idea into my setup.

Bill.

[tasos]

mark, I think you have to much live rock above the benthic zone thing.....I though that lr needs more water flow to keep the debris out of cloging it.......I will let others speak, I am not to familiar with this method......

[snorvich]

I plan to have a layer of live rock rubble that is about 1 inch thick rather than filling the area like you have. I too think that it is too much live rock for the purpose.

[mark caruana]

Ya, I wondered that myself. Though to be honest there really isn't much debris on the rocks themselves, and my skimmer has an MJ 1200 pumping the water through.
Considering this, why else do you guys think there's too much rock? I personally don't think there is too much, but I would really like to hear some others' opinions.
Thanks for your replies Tasos and snorvich

[stan the man]

Mr Wilson,
Thanks for expanding on an idea that I have long wanted to try, but avoided due to lack of knowledge on my part. I am designing a 135/150g sytem (probably a year or so out on this) that will be fish only(although I may sneak some soft corals in there), and want to incorporate this type of filter system. I will be using one side of the display for an internal overflow wall, in which I am leaning toward a DSB, with skimmer flow/return pump matched at around 600-700gph. If I need more circulation in the display, I'll add an enclosed loop.
My question is in regards to the DSB...If I have a 3"x18" by 18-24" deep overflow area in the display tank, what kind of depth would I employ there? With the use of a Durso standpipe near the top of the overflow, will flow over the DSB be sufficient enough?
Thanks again for taking the time to contribute to this post!

[stan the man]

Mark,
How deep is your macro algae layer which sits on top of the rubble? I thought the rock layer looked pretty deep too, but if the water flow is there, I don't see anything wrong with it as is. I'd just make sure that the reason detritus isn't settling isn't due to low circulation levels down in the rock.
I've also got an Aqua-C Remora, and will be using a similar plumbing method to yours on both my current 75g and the new tank I'm starting to design.

[mark caruana]

Stan,
the macro layer is about 4" to 5". The refuge is 12" deep; macro-4 to 5", rubble 4 to 5" and benthic zone 2 1/2" deep. I piled the rock up to the surface where the skimmer feeds to slow the flow going downward because, like Mr. Wilson said, water will find the path of least resistance. And the flow is definitely slow below the rubble.