Refugiums For Dummies

[Mike O'Brien]

It seems like everyone is talking about refugiums lately. What are they? what do they do? How do I build one? These are common questions. In this post I would like to answer these questions, and shed some light on this popular subject.

What is a refugium?

A refugium(fuge for short) is an area where plants and animals can thrive without the threat of predation. Usually located in a separate aquarium, but can also be inside the display, or hanging on back. The fuge shares water with the display tank.


What do I put in a refugium and why?

Most fuges contain live sand or mud. there are several products available specifically for this purpose, bio-sediment and mineral mud to name a few. Regular sand works fine too. Live sand should always be added to provide a diverse population of sand dwelling critters. You cant get these with packaged sand. With a deep layer of sand, natural nitrate reduction can take place.
On top of that live rock is used for additional filtration and a good place for pods to reproduce. This is especially beneficial for fish like mandarins and others that eat pods. The macro algae will also attach to the live rock.
There are many macro algae that are suited for the refugium, caulerpa, and chaetomorpha being the most popular choices. Gracilaria varieties are also useful for herbivores like tangs. Mangroves can also be grown, and make interesting nitrate reducers. The plants are used as a means of nutrient export. By pruning you essentially remove dissolved organics from the water column. The plants also produce oxygen which cleans the water and helps maintain Ph.
Shrimp are also common in a fuge. A good pair of breeders can supply lots of fry. Along with the large pod population produced in the fuge, corals and fish in the display will have an ample supply of live food. The sand dwellers are another important food source when they reproduce.
Fast growing corals can also help reduce DOC's. Xenia and Green Star Polyps are popular choices. If you plan on using corals just be sure to provide the required lighting.
Lighting is a simple matter, as no special lighting is required normal output bulbs can be used with success. A minimum of three watts per gallon is recommended. Running the lights opposite the display can help limit daily Ph fluctuations due to photosynthesis.

How do I build a refugium?

There are as many way's to set up a fuge as there are reefers out there. I will discuss two of the more popular styles.
First is above or on the side of the display. This is a simple method, a small pump is used to feed the fuge, and the return can be a simple siphon tube or a bulkhead with a drain pipe. This is the preferred method
because the return does not go through a damaging pump.
Second in or near the sump. Since most reef's already have a sump this is a very popular method. Like a normal sump an overflow is used and water is pumped back to the display. A series of baffles is used to contain the fuge and keep things from being sucked into the return pump. Although not everything is damaged by the pump, there is of course a percentage that does.

I believe that a refugium is a great addition to a reef system. Not only can you create a very functional natural filter, but it can also be very interesting to watch. I find myself watching the fuge as much as the reef.
Here is a few different diagrams of refugium ideas.


http://i5.photobucket.com/albums/y157/Mike0101/20galfugesump.jpg

http://i5.photobucket.com/albums/y157/Mike0101/system3.jpg

Here is a picture of the plumbing setup I used on my side by side setup.

http://i5.photobucket.com/albums/y157/Mike0101/plumbingdescription.jpg


My current sump refugium, this one I am not using algae.

http://i5.photobucket.com/albums/y157/Mike0101/mysump.jpg


Mike O'Brien 3/5/04

[thomas1102]

thanks for the 411 mike :P im looking into building a fuge fo my 90 gallon. nothing big, just thinking about a ten gallon tank :P

[Mike O'Brien]

your welcome. and good luck with the project. DIY is the way to go. :lol:
mike

[Snausages01]

your welcome. and good luck with the project. DIY is the way to go. :lol:
mike

I agree...My next one will be DIY and be almost the same length/size of the aquarium (just build it into the stand). :) However, it will still be made out acryllic or lexan.

[Reefer4life]

quick question, Is there supposed to be more live sand in the Fuge than in the display tank??

[Mike O'Brien]

there are no set rules but a deep sand bed will promote the right environment for NNR natural nitrate reduction where anoxic bacteria complete the nitrogen cycle. some people dont like the looks of a DSB, so for them a fuge would be a good place for one.

[thomas1102]

thats me :mrgreen:

[Reefer4life]

Ok this is a silly Q,
Mike, You mantioned that u can build a Fuge from above or beside the Display tank..Is there anything wronge with it going under the tank?

And another Q,
Is it bad to set up a Fuge on an already existing reef???

[Mike O'Brien]

thats what I meant about in or above the sump. alot of people are doing it that way. I like to look at the fuge too, so I went for the side.
adding a fuge at anytime is a good idea. you can cycle it seperatley if you wish, when the numbers are good start the pump.

[Reefer4life]

oh alright. heres my idea for the fuge. if theres any objections let me know:

What i want to do in the future is put up a 125G reef. I will drill in a couple holes (1" thick) on the back top left and right those will work as an overflow. the water will drain down into the 55G Fuge and ill have a pump to pump the water back into the 125. Problie 1 hole will work instead of 2, but thats the basic idea.

___________________________
| 0 <-Drilled 1"overflow- --> 0 |
| |
| 125G reef |
| |
| |
|__________________________ |
________________
| |
| 55G Fuge | Pump will bring back up
|_______________|

[Reefer4life]

lol i guess my display didnt work like i thought it would

[Mike O'Brien]

you can buy that tank "reef ready" with two built in overflows with standpipes and prefilters.

[Ludwigia]

You know, there is one aspect of a refugium I have never seen addressed. If you put it under your tank, remember the lighting. Heat rises!!!

[Snausages01]

You know, there is one aspect of a refugium I have never seen addressed. If you put it under your tank, remember the lighting. Heat rises!!!

:?:

That shouldnt be too much of an issue as most lights are fairly low in power, mines only 18 watts. Now if you were doing some major lighting for corals under there then it maybe a problem, but Im not sure how much of an issure it would be as the sand may act like insulation. If thats a problem though just add a fan or two.

[phillipm]

:lol: :D :) There is plenty of grey matter on this site which is good to see. That second diagram with the tank holding the pump & skimmer you could use egg krate to partition half that off & put crushed coral in to make a bug farm. Some people have a frag tank taking the flow from the fuge before it goes back to the display. I saw a hangon job once in a mag. It was about 4ft L x 10" front to back & about 26" deep with 10-12" 0f sand & a heap of bueatiful red caulerpa It was a picture in its own right. A working picture you might say. Some people say a fuge should be 20% of the display capacity. I reckon 50% if you can swing it.

[oceanzathome]

Thanks for those tips..I plan on a hang on fuge.That is my only option.Is it a bad one?Also I have lots of air bubbles forming on the bottom of my tank and on my LR everyday .Do you know what this is from?It looks like its coming from under my :roll: sand!Is this bad?

[phillipm]

:) The above could be your problem. Dont agitate the surface for a while & turn off the skimmer for an hour & see what happens.

[elvictre]

Hey Mike, I have a question. I am going with not linking my tanks....too many opsticals. Anyway I will be going with a sump fuge for my 75, I was gong to use a 38 gal tank that would fit under my tank. Can I use a glass tank and use plexi to build my colums? Or should it all be glass? Also does a UV interfere with a fuge? I have a UV on my return line, I don't want this killing my pods.

Thanks

Vic

[Mike O'Brien]

yeah the plexi will work fine. The silicone will hold it good, and the pressure will be equal on both sides. Alot of people use UV's, and still have large pod population. You might want to change the placement of it though so everything from the fuge isn't forced to go through it. I'd probably run it out and back into the sump or something like that, or maybe split the drain line and send some through the UV

[elvictre]

Thank You Mike, I appreciate this. Thanks

[Mike O'Brien]

Your welcome. If you make it like the pic, there should be no bubbles getting to you're return pump. Good luck with it.
Mike

[phillipm]

:) You have water going from the fuge to the skimmer I dont like that idea.

[Mike O'Brien]

Though some things may be removed by the skimmer, I believe that placement of refugiums and skimmers really dont matter.
Most systems like that have at least 500 gph going through them, and no part of the system is very efficient. For a given time the skimmer doesn't remove everything that goes through it, the refugium doesn't remove everything that goes through it, the tank doesn't consume all that came from the refugium. Even with a measly 500 gph thats 12000 gpd going through the system. So lets say in that diagram 250 gph run through the fuge, half of the output gets skimmed and half of whats skimmed gets removed, that is still 4500 gpd of enriched refugium water making it to the tank.
The only way I could see a problem would be the entire output of the refugium plumbed directly into a skimmer, even then not everything would be removed by the skimmer.

[phillipm]

I can just about hear those plants sucking up all the nasties. I would sprinkle a bit of coral rubble around the base of the plants and you'll find some of the bugs will crawl up into the plants. I've been watching mine, and they seem to clean the plants of captured particles. Good job!

[TxNewbie]

New to the hobbie, and I'm in process of aquiring everything I need to set-up a reef tank, but have a question or if someone could send me in the right direction. Would a good set-up have the water from the tank flow into a wet/dry filter and then into a refugium/W protein skimmer attached, or is this overkill? Would appreciate the info.


Just purchased a 75 gal Oceanic Reef Ready Tank

[Mike O'Brien]

It wouldn't be overkill, however most people are now using liverock in the wet dry instead of bio balls. As far as I'm concerned placement of the different components doesn't matter much, but I like the diagram already posted, just replace the wet dry for the sump on the left.

[gregb]

Mike give us a look at that great tank of yours. Phillipm. When did the site come back on? its all & shiney.

[Mike O'Brien]

Here you go Bud. I no longer have this setup, but it was nice.
http://i5.photobucket.com/albums/y157/Mike0101/DSCF0014.jpg

[Roscoe]

Mike You said Fast growing corals can also help reduce DOC's. Xenia and Green Star Polyps are popular choices. If you plan on using corals just be sure to provide the required lighting.
Lighting is a simple matter, as no special lighting is required normal output bulbs can be used with success

What is no special lighting? Flourecent aquarium bulbs? Thanks Roscoe

[Mike O'Brien]

No special lighting is required for growing algae, by that I mean you can use about any bulb you want, from an regular incandescent to power compact's to metal halides.

As far as coral's you need to give them the proper lighting level's, so you will usually need more light than it would take to grow algae. Not that algae doesn't like brigtht light's. At the time I was growing corals in my refugium I was using a 175 watt MH.

[crabalot]

I am going to start a reef tank with fish in the near future. I have only had freshies, and my latest tank is a 45gal bowfront. So, do I need a sump and a fuge, or does the fuge take the place of a sump? I see by research there are sumps with a fuge incorporated. I think if just a fuge is ok, it looks like it should be above the main tank with gravity overflow. Does this sound reasonable? Then how powerful should the pump be to get to the fuge? Is submersable or external pump better? Should the skimmer be in the main tank or in the fuge/sump? Any suggestions on a good brand (or one to avoid) for pumps, skimmers, powerheads, etc?

[Mike O'Brien]

Personally I don't think a fuge should replace a sump. Ideally you can run you're skimmer heater and other equipment in the sump, and have the refugium seperate. Yes above the tank is theoretically the best place, but IMO anywhere will work. Pump's are not that damaging to pod's. Generally a smaller submersible pump is used to supply water to the refugium. High flow is good to have inside the fuge, but you don't need much turnover. I used a 60 gph pump on my side by side refugium display.

[JMhome]

That was a very informative post! I will set one up on mine also under my show tank.
Question.. You mentioned to run the lights opposite the display due to ph, how long do you run the lights? DO you split the time 12hrs & 12hrs?

[Mike O'Brien]

Basically yes, or you can run the refugium 24 hrs.

[JMhome]

Thanks for the reply!

[crabalot]

Thanx a bunch for the help. I'm learning quickly how to shop for stuff or just do it myself. I used to do commercial electrical construction so I believe I can create a neat reef/sump/refugium at a fraction of the cost. I bought a 20gal tank for $10.00 at goodwill...sure beats $300-$400 for refugiums I see on line! I talked THE BOSS into letting me spend the money if I have seahorses in the refugium. Any tips on keeping seahorses?.

[ZOKU]

*nod* Good thread!! :)

[phistio]

Any tips on keeping seahorses?.

i discourage you trying to keep seahorses...they're very delicate creatures.

but...

www.seahorse.org is great for learning a LOT more information on them.

[litebrite]

Hello. I just solved my Nitrate problem and ready for the Refugium. This seems like a dangerous question... And no one ever talks about it. What happens if I turn the light off at night when I am sleeping? I know the process stops, but will something bad happen? Will it start producing Ammonia or Nitrate or something even worst? Can I use a simple 4 watt night light to keep it going at night?

Thanks
Dan

[David_P]

At the end of the photoperiod, the final stages of photsynthesis take place. Some people run their refugiums lit, 24/7 to try and keep macro aglae from going "sexual". Personally, I use a reverse photoperiod for my systems. When the display is lit, the fuge is not. When the display falls into darkness, the refugium lighting comes on. It helps to keep Ph swings to a minimum.

I prune my macro regularly, for use in the seahorse tank. In the years I've used the various macro algaes, I've not had one go sexual on me.

Dave

[litebrite]

What do you all think about this? This was my idea.

I was going to build this refugium directly in to the aquarium it self with a clear glass divider in the back. It would share the light from the tank in day and darkness at night. The plants would give me something really pretty to look at in the background. I was going to use mostly seagrass and some macro algaes.

Questions.
1. What does going "sexual" mean.
2. Will they do harm to the water or oxygen levels in darkness?
3. Can I use 2x the live plant to make up for half the hours of light?
4. Will I benefit from a refugium that will be in darkness half the time.
5. I heard that it "Reverses" in darkness. What ever it removes in light it puts back in darkness... is this true?

Thanks.
Dan

[jxb647]

if you use an algae like Chaeto you do't have to worry about that cause it can't go sexual. Also it has the added benefits of not attaching to anything and removes lots of nutrients

[litebrite]

I am trying to find out what will happen if you set up a refugium with out light? What will it do?

I have a 5 foot tank. I am going to split it in 2 sections. I wanted to make the whole back half of the tank one super long refugium because I like how the grapes and grass look. Then put my fish in the front part. I was going to turn off the light at night. But will these sexual plants hurt the marine life in darkness. What will they do with out light? I know they go sexual, but besides release CO2, what else can go wrong. Is that enough CO2 to hurt my fish.

[Mike O'Brien]

The process doesn't stop even though photosynthesis will. The alga is still respireing, it doesn't just switch from producing oxygen to producing CO2, it is a ratio that just swing's in favor of CO2 while the light's are out.

[Gin & Tonic]

I keep seeing references to issues with the refugium's macro-algae "going sexual".

What exactly does this mean?
What are the potential repercussions?

Is this just the algae going into a reproductive phase and releasing spores into the tank?
If so, wouldn't this be a food source of the all the filter feeders in the tank?
Is a major algae outbreak likely?
Would it probably exceed the consumption rate of my janitorial herbivores?

[Mike O'Brien]

Thing is as it releases those spores it is dying and very rapidly disintegrates into the water. In this case there is alot of other nasty stuff being released into the water. Another problem is oxygen depletion from the bacterial bloom's that come along with the event.

Caulerpa is an algae that you do not want in the display tank. It is very invasive and can really take over the tank in a short time. This is why I recommend chaetomorpha. It doesn't go sexual, doesn't attach to the substrate and removes more nutrient's compared to caulerpa.

[saltythumb]

Hello, The question I have is that I have a 46 gallon bow front tank and cabinet stand. As you know, the cabinet is curved as well to match the curve of the tank, thus making it difficult to construct a refugium to fit underneath the cabinet due to the middle of the cabinet being deeper than the rest. Any suggestions?

Thanks,
Salty

[FishTankFreddie]

well how big is the wet dry? you could just convert that to a fuge.

[Europa]

Yeah, just remove the bio-balls from the wet/dry and add the baffles and a fuge light.

[Mike O'Brien]

Hello, The question I have is that I have a 46 gallon bow front tank and cabinet stand. As you know, the cabinet is curved as well to match the curve of the tank, thus making it difficult to construct a refugium to fit underneath the cabinet due to the middle of the cabinet being deeper than the rest. Any suggestions?

Thanks,
Salty

Others have just used smaller bow fronts as sumps.

[newereefer]

on the plumbing asspect, using a over flow how do i keep the water from draining out of my tank and into the floor. I have the overflow box, return pump, but how do i plumb it for a under the tank fuge?

[Mike O'Brien]

Once the tank is full of water, the "over" flow, only drains what is pumped into the tank by the return pump.

http://www.reeflounge.com/showthread.php?t=22009

[newereefer]

how about the plumping

[Mike O'Brien]

You can use flexible tubing or pvc pipe. Pretty simple actually.

[newereefer]

should i use a check valve on the return or what do u suggest?

[Mike O'Brien]

You're better off with an appropriately sized sump, then you don't need it unless you plan to have the return lines submerged deeply. I put a ball valve on mine, but it was a waste. It never gets used.

If you use pvc, the important part is to use threaded unions so you can disconnect the plumbing from the tank and the pump easily.

[newereefer]

thank for the info mike, also i tried putting a 20 long that i already but baffels in under my tank and it wouldn t fit so i guess i am going to have to use a smaller fuge any suggestions?

[Mike O'Brien]

Maybe some sort of Rubbermaid container. Or a custom acrylic tank. Depends how much you want to spend or how handy you are.

[Europa]

I put a ball valve on mine, but it was a waste. It never gets used.

You'll use it if you ever have to work on or replace the sump though, right?

[Mike O'Brien]

Actually, I just unplug the pump and the unscrew the unions. I have one at the pump, and one at the tank bulkhead.

[saltythumb]

Thanks. that's a good idea using a smaller bow.. will it give me enough space though??? I have thought of converting my current wet/dry however... it is a amiracle slimline and the area where the bio balls are kept is rather small to house a refugium.. I don't know. In this instance, it is more of a pain in the ass that anything else to construct something myself. I have researched and used the new pro-clear refugium on other tanks, but I don't believe they make one small enough. Has anyone heard of the new "eshopps refugium/wet dry sumps? Their small version I believe the measurements are 20x10x16 would fit.

As always...thanks,
Salty

[Europa]

I still think converting your wet/dry would be the easiest thing to do. It's as simple as removing whatever dividers are in there and adding 3 plexiglass/acrylic/glass baffles. Piece of cake and it would be very cheap.

[gsxunv04@aol.com]

i vote you go to the nearest pet store and pick up a 20 gallon tall aquarium and stop by home depot/lowes on the way home and pick up three baffles cut from glass and a tube of DAP, or similar, aquarium silicone

[miket]

i vote you go to the nearest pet store and pick up a 20 gallon tall aquarium and stop by home depot/lowes on the way home and pick up three baffles cut from glass and a tube of DAP, or similar, aquarium silicone

Will that fit inside that bowfront cabinet? I think that's the issue.

Is it one of these ?
http://www.seatrademarine.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=ASL350B&Category_Code=FWD

I agree with Europa that converting would be easiest. All you need is one or two baffles, a ball of macro algae and a light and you got a small fuge/sump. I would raise the water level a bit higher but only if it can handle the overflow in a power outage.

If not, sounds like a standard 10 gallon would fit. I used to have a 10 gallon sump/fuge on a 20 gallon long. It would still be better than no fuge.

The small space where bio-balls were will still grow plenty of macro algae and become a great nutrient export. Macro algae is a great pod breeding ground too.

Refugium's rule, no matter how small, it helps. I had a tiny HOB one that had a 3"d x 10"w x 8"h macro area with an 18w light (on a 10 gallon). It never had algae problems and would fill the fuge every week with macro. I would only leave a golf ball sized chunk.

I my new 125 gallon, I remove a 3 gallon bucket packed with macro algae every week and a half, That is only 3/4 of the algae, the other 1/4 is seed for new growth.

- MikeT

[gsxunv04@aol.com]

it should, that why i said 20 tall and not 20 long, if not then just get a 10g or something, if its that little of a space i would remotely locate it, make a cbinet to the side of the stand and put it in there. i would take this time and efforts to not skimp on sump/fuge size. a 5g fuge, although better than no fuge at all, if pretty worthless on that size tank.

you can always go get some 1/4"-1/2" acrylic and make your own...custom fit

[saltythumb]

Thanks for your input. I found a design for a ten gallon refugium that I tweeked a little bit. I plan on using the three pieces of plexiglass for the bubble difuser before the water gets to the return pump. Being that it is a smaller sump...do the pieces of plexiglass need to be the recommended one inch apart or can they be a little closer to make the other area of the sump a little bigger???

[Europa]

Are you going to put a skimmer in it?

[saltythumb]

Are you going to put a skimmer in it?


I was probably going to use a hang on model to give me more room in the sump. Either hang on the sump if it can fit, or on the back of the tank... CPR, aqua c or the new coralife skimmer.

[lost4ever]

do i have to cycle my fuge before adding it or can i just add it on so it would be similar to like a water change, just adding more water to the already stable tank?

[gsxunv04@aol.com]

if you put rock and sand in it i would waite, but if its bare bottom soley with macro algae(hopefully chaeto and not caluerpa, unless you got some tangs or rabbitfish) as i would advise you to do so(unless you have a bare bottom tank, and then i would put a dsb in the fuge, or better yet have a rdsb) then i would just add it in line

and salyth thumb, i would recomend you avoid a HOB skimmer at all costs

[saltythumb]

Will that fit inside that bowfront cabinet? I think that's the issue.

Is it one of these ?
http://www.seatrademarine.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=ASL350B&Category_Code=FWD

I agree with Europa that converting would be easiest. All you need is one or two baffles, a ball of macro algae and a light and you got a small fuge/sump. I would raise the water level a bit higher but only if it can handle the overflow in a power outage.

If not, sounds like a standard 10 gallon would fit. I used to have a 10 gallon sump/fuge on a 20 gallon long. It would still be better than no fuge.

The small space where bio-balls were will still grow plenty of macro algae and become a great nutrient export. Macro algae is a great pod breeding ground too.

Refugium's rule, no matter how small, it helps. I had a tiny HOB one that had a 3"d x 10"w x 8"h macro area with an 18w light (on a 10 gallon). It never had algae problems and would fill the fuge every week with macro. I would only leave a golf ball sized chunk.

I my new 125 gallon, I remove a 3 gallon bucket packed with macro algae every week and a half, That is only 3/4 of the algae, the other 1/4 is seed for new growth.

- MikeT

Seatrademarine...great site. Just so happens the company is owned by a friend of mine. Great business, great help, very informative and very competitive prices. would recommend seatrade anytime.

[TANSTAAFL]

Question. Earlier in this thread, Mike mentioned using PVC to plumb the drain from an overflow box. I was told that hard piping the drain from the overflow box could cause the box to crack. Is this true? I really wanted to hard plumb the drain so I could get rid of the droop in my flex hose. This droop seemed to be a haven for algae growth.

[reeferhead]

...I was told that hard piping the drain from the overflow box could cause the box to crack. Is this true? I really wanted to hard plumb the drain ...

Interesting... I was hoping to hard plumb my drain too. Why would it crack the overflow? can anyone attest to this?

[Mike O'Brien]

It's only if you or something else was to bump up against the plumbing. That would stress the area around the bulkhead. It's not the plumbing itself that's doing it.

[gsxunv04@aol.com]

mine is hard plumbed, and no cracking going on. Like mike stated, it would take a bump(a heavy one at that) to crack it.

[reeferhead]

Mike, How about throwing a couple inverts in the fuge? I have a 4inch bed in my fuge, some LR rubble and some chaeto. Any recomendations? I'm just not sure about them getting caught in the bubble trap or return. thx

[Mike O'Brien]

I'd avoid them mostly, maybe just a few snails.

[Europa]

I have 4 snails in my sump, no hermits.

[Mike O'Brien]

I've used hermits, but they always got stuck in the skimmer or the return pump. They climb over the baffles.