Let's Talk About ~Refugiums~

[Jonathan G.]

speeking of fuges does any one make a better bigger hotfuge than cpr

i asked a similar question earlier in this thread and got no response but it was on how a HOT fuge like the CPR brand compares to a plumbed one made out of like a 20g tank.

 

[ladygator]

UV and Pods?

Hello - I'm not sure if all pods passing through a UV light will be done in. They actually have very good defenses to UV radiation because they end up in very exposed areas when their tide pools dry up. They have the stamina to crawl across what would be miles to a human being to get to a new pool of water. It has been demonstrated in arctic pods (think of how red Cyclopeeze is) that they can change coloration to combat the oxidation effects of UV radiation. I have recently helped out in a marine lab near my place in Santa Cruz and I placed a filter on the outflow of water which was passed through 2 sand bed filters, 3 canister filters in size ranges from 100 microns to 5 microns, and UV filter - guess what - there were still copepods coming through. We figured there was a leak in the canister filters, and the UV bulb was replaced, I believe to increase the chances of removing any remaining pods. These guys are tough!

 

[NaH2O]

Nutrient Export

ladygator - thanks for the insight on the UV vs. copepods. I feel a little better, at least knowing some may make it through my unit. I wonder if their ability to propagate is hindered if they survive the ultraviolet?

As mentioned earlier in the thread, one evolved purpose of a refugium is nutrient export. In order to export the nutrients, something has to be harvested (whether its a macroalgae, coral like xenia, aiptasia, or cyanobacteria).

Caulerpas do have issues of their own....I pointed a couple of threads earlier in this discussion talking about the toxins. If a choice is made to use an algae like caulerpa for nutrient export, how can we utilize it without causing harm to the system? One way is to not use scissors to prune the algae. They will leak their toxin and gelbstoff (the yellow stuff removed with carbon) into the water. A better method is to pinch an area, hold the pinch for a few seconds, then pull that part off. It would be a good idea, if possible, to do the pinching in old water (i.e. from a water change) to rinse the plant off and remove any of the toxin released.

How often do macros need to be pruned? Does anyone feed their macros to fish in the tank?

 

[Marc]

One way to keep your refugium clean is the stir up the water well when doing a water change. Get that "mud" out of there with each water change. I just pump out the muddy water, and replace it with clean water.

And occasionally, stir it up so the detritus flows back into the display late at night for the corals to munch upon while the fish sleep. By getting it waterborne again, the skimmer may remove some.

I actually strongly recommend refugiums, and have them on my tanks.

Regarding macro algaes, if you are a caulerpa owner, I'd keep the light on over the refugium 24/7. When I had the refugium on the reverse-lighting schedule, it kept going sexual and dying. Very frustrating, even the LFS had no problem charging me for more each time I replaced it. Once I left the light on 24 hours a day, it never happened again. If it does go sexual, the green fluid leaks out of the plant like blobs, and the water in your tank turns green. It usually clears in a few hours (by morning), and if you have a clam in your tank it will have had a nice meal for sure.

Cheatomorpha is a great macro that doesn't require 24 hour lighting, and stays green even if it is shaded by more macro above it. No matter how dense mine has grown, the bottom algae is just as green as the upper section.

When it comes to pruning caulerpa, I found that using a scissors worked better for me than tearing it. Like Nikki suggested pinching, I think scissors to pinch the stem a bit as it is cut, and helps prevent losses. Which cheato, when you prune it, be sure to gently tug apart the rest of the clump a little to encourage more growth from the plant.

 

[Forestal]

Great thread and info Nikki... I had a 55 fuge on my 55 reef, used a well seeded DSB and live rock and my pods were huge (all types - i used my microscope to look every now and then)...i agree on the caulerpa...i think it may affect some coral growth, especially sps...chaeto and gracilia and even mangroves are great but they are slow growing....i sometimes use xenia as a nutrient exporter...grows faster than some macro and can make lots of frags

 

[cheeks69]

Randy Holmes-Farley:

Nevertheless, growing and harvesting macroalgae (Figure 2) remains one of the best ways to reduce phosphate levels in reef tanks (along with other nutrients). Tanks with large amounts of thriving macroalgae rarely have microalgae problems or excessive phosphate levels that might inhibit calcification of corals. Whether the reduction in phosphate is the cause of the microalgae reduction is not obvious; other nutrients can also become limiting. But in a certain sense it makes no difference. If rapidly growing macroalgae absorb enough phosphorus to keep the orthophosphate concentrations in the water column acceptably low, and at the same time keep microalgae under control, most reef keepers will be satisfied.

From the same article
Summary of Phosphate Reduction Methods

The big winner is macroalgae growth. Not only does it do a good job of reducing phosphate levels, but it reduces other nutrients as well (e.g., nitrogen compounds). It is also inexpensive and may benefit the tank in other ways, such as a haven for the growth of small life forms that help feed and diversify the tank. It is also fun to watch. I’d also include in this category the growth of any organism that you routinely harvest, whether corals or something else

http://www.advancedaquarist.com/issues/sept2002/chem.htm

 

[gobyit]

I like the idea of having a refug. but I am concerned that the pods. and the like, would be sliced, diced,and pureed on the way up to my display tank, because of the pump!!

 

[piercho]

With regard to the questions on HOT refugia:
The CPR refugia are the only HOT refugia I am aware of. The narrow width allows them to be placed on one end or behind the tank without being too obtrusive. The 4" width is wide enough to make use of duplex power compact lamps to illuminate the refugia. I have not used one of these and am just stating the obvious.

I've have made DIY above-tank (gravity) and below-tank (sump) refugia. I prefer the sump refuge setup because it just seems less problematic to plumb and easier to get higher flow rates through it. If you are using the refuge mainly as a vegetative filter than, IMO, you want to pass as much tank water through it as possible (high flow rates).

Refugia that gravity drain to the main tank are trickier. IME you want the refugia to be significantly higher than the main tank, so the refugia outlet is at least 6 or more inches above the main tank water level. You also need a backup outlet so that the refugia can't overfill and flood if the main outlet plugs. To raise the water the extra distance, you can use a separate pump from the sump or tank, have a side-stream plumbed from the main return with a valve in the tank return line to get the extra pressure for the side-stream, or return ALL the sump water through the refugia. All of these plumbing solutions can be tricky. To add to that, a refugia above the main tank is often visible by necessity, so you may not want a franken-plumbed plastic storage bin with a flood PC resting on sticks for your visitors to see. In other words, you are likely to spend some money on components to make it look decent, where a sump refuge can be built cheaply as no one sees it.

Another DIY option is to use a HOT power filter as a refugia. For instance a Tetra PF500 holds about 2 gallons in it's large filter area. Don't use the filters, find a way to mount a PC above it, and find a way to put rubble in the filter compartment (forget sand here) without jamming the pump and you've got a 500GPH gravity-return refugia that can also heat your tank.

A forgotten way to establish a refugia is to make it internal to the tank. Rubble piles or an eggcrate "box" hidden under the rockwork are common options. Finely-branced rockwork is a refuge area. As long as the larger predators cant penetrate the area, its a refuge. Old heads of close-branched coral like Pocillopora become refuges as they grow outward. In these cases, these areas are strickly refuges, and don't serve a purpose of export. IMO, these are the most effective areas of "refuge" for microfauna to recharge/feed the tank.

So:

IF you intend to have a vegatative filter, I would set up an area mainly for that purpose, and consider it a "refuge" as a secondary objective. IMO a sump setup is the least problematic way to create a vegetative filter. IF you intend to create refuge for the purpose of feeding/recharging the main tank with micro-fauna, IMO you can accomplish that in how you set up the main tank by creating refuges within the tank. As far a refugia that gravity feed, IMO, they are mechanically problematic and probably don't accomplish either goal (vegetative filter or food source) as well as other options.

 

[NaH2O]

Good posts everyone! Gobyit, Welcome to Reef Frontiers!!! I wouldn't be overly concerned about the pods getting chopped up by your pumps, as I believe a vast majority are small enough that it isn't too much of an issue.

Since we kind of touched on macroalgae and exportation....I thought I'd toss this quote out here:

In order to make a meaningful comparison, we need some standardized measure of growth, however, because a "stalk" of one alga and another may be quite different. The most common measure is "specific growth rate" in which the growth is measured in mg per gram of algal body weight per day, or percentage increase. So, to compare the specific growth rates of some of the more common species that I can find data for, the maximum growth rates appear to be something like this:

Halimeda: ~2% / day (10-20 mg/g/d)
Dictyota: ~ 10% (50-100 mg/g/d)
Padina: ~ 10% (75-100 mg/g/d)
Caulerpa: ~ 10% (50-100 mg/g/d)
Thalassia: ~1.5% (10-15 mg/g/d)
Palmaria: ~15% (doubled in 1 week)
Enteromorpha: 20% (7 fold increase in 1 month)
Gracilaria: 6-10% / day

However, if you want to maximize the nutrient export, the clear winner in field experiments is the cyanobacteria Lyngbya, which grows at a rate of roughly 5 times that of any of the common macroalgae in the trade, and adds an average of about 35% (300-400 mg/g/d) of it's weight per day! But it would be a pain to remove and looks like hell....

So, obviously there is a bit of a trade-off that we have to take into account when we talk about nutrient export. We want something that grows fairly quickly to remove nutrients, but also you want something that is easily controlled, harvested, and doesn't make your tank look like a cesspool. The other consideration is that most of the common algae on the reef (e.g., Dictyota, Padina, Caulerpa) are often highly chemically defended (otherwise they are eaten by herbivorous fishes), and most people seemt to be trying to avoid such species in their tanks. So you have to balance the specific growth rate against the suite of secondary chemicals which these species release and the ability to harvest them for nutrient export. So, taking all of this into account (growth, ease of removal, chemical defenses, probability of overgrowth, appearance, etc.), my favorite choices for macroalgae in my own tanks is typically Halimeda or Ochtodes if included in the main display tank, and Enteromorpha, or Graciliaria, if included in a refugium or a sump....


mike

I also want to talk about substrate in refugia. Some hobbyists utilize the refugium for a remote sandbed. If anyone is doing this, do you try to set it up so as much detritus as possible makes its way onto the bed to be broken down? Or what purpose does your sand serve? How much sand goes into a refugium? Also, don't know how much of a substrate this is for refugia, as it is filtration, but Miracle Mud is another that people use for substrate. Here is a little info on Miracle Mud:

Miracle Mud Setup Instructions
Miracle Mud Analysis
Single Post - Miracle Mud experience

 

[jlehigh]

Just to throw in what I am growing, I have a large patch of Chaeto I harvest however within the chaeto patch I have a patch of Red Cyno (about 6" diameter at harvest time) which I also harvest by simply removing the Chaeto it's on. Oddly enough it does not seem to grow all that fast, but definately grows. I may be playing with fire but to date it only grows in the refug and I do not have any in my display.

Also note the thread I started sharing my experience with butter/steamer clams in my display and refugium.

I do not use a substrate in my refugium. Just live Rock (smaller pieces), macro algae, and manilla clams.

 

[Angelscrx]

Ok I know the chopping thing with pods has been covered but I thought I would share an example. In my tank I have a scooter and a Mandarin which both feed on pods. Needles to say the population was diminishing. I have a fuge/sump and the pod population was very well established along with mysis shrimp and artemia. My pump had a prefilter on it so I wasn't getting anything to the tank until I took the prefilter off. Within a week there were pods and mysis every where in the main tank. I was concerned with them being chopped up too but they made it through healthy and running.

As for the UV sterilizer couldn't you put it on the drain side of the plumbing as to not hurt anything coming back in to the main tank? Either way the water is being sterilized? Just a thought!

 

[Maxx]

The only problem with that is the flow rate through the UV sterilizer. Slower flow rates means more time exposed to the UV, means more effective UV. You really dont want to be slowing the flow through your drain, becuase then you'll have to be tweaking the flow rate of your pump to match the flow rate of the drain....thats just a nightmare....

Nick

 

[Angelscrx]

The only problem with that is the flow rate through the UV sterilizer. Slower flow rates means more time exposed to the UV, means more effective UV. You really dont want to be slowing the flow through your drain, becuase then you'll have to be tweaking the flow rate of your pump to match the flow rate of the drain....thats just a nightmare....

Nick

I see your point but then again isn't that why we try to match our return pumps to what we are draining? I mean you don't want to be draining 1000gs and then pumping 3000gs and then trying to turn down the flow right? I don't have a UV in my tank and it's small enough I don't have the major flow issues but I will be setting up my 150g here real soon and may have a difference experience with it.

 

[NaH2O]

The only experience I have regarding where the UV goes in a set-up is what the instructions for my unit say:

Where do I install my UV?
The best place to install your Aqua Ultraviolet Sterilizer is after the filter. If an after the filter installation is not feasible, your sterilizer can be installed before the filter, but it will take a little longer to work. If installed before the filter, be aware that a small rock passing from the pump can break the quartz sleeve.

and

Hint: The UV should be installed after the filter on the return line. This ensures the water is clear of debris and impurities that could inhibit the disinfection process.

(The UV can be installed before the filter, however, it will take longer to work.)

From the Aqua UV - Installation instructions

Here is the thread where jlehigh talks about his butter clams Butter clams in the reef

On a side note, does anyone deliberately feed their refugium?

 

[Angelscrx]

I don't feed the refugium.enough stuff gets brought in from the overflow that I don't have to IMO. Everything seems healthy in there!

 

[dgasmd]

I don't understand why I never got a notice saying the thread had been replied to, but here it goes anyway.

Nikki:

I stand corrected on the water born pods. However, I think the original questions to whether refugiums are good or not and how good should maybe follow what are they trying to compensate for in the first place. Let me explain.

If you have a huge fish bioload and need nutrient export adding a refugium is a good bandaid, but the real solution is to decrease your fish bioload. Now, I for one love fish and maybe that is not an option I want to take up, so the refugium in that sense may buy me a little time and help me out a little. In addition, I would have to step up water changes and a host of other things to make up for the increased production of waste disproportionate to my water volume and filtration capacity. Then comes the question of pods feeding fish. Is all that contraption and extra equipment (and yes this is coming from me ) really worth the nutritional content of some pods? Well, it depends. If you have a 20g tank with a pair of mandarins I would say very loud YES YES YES. But, if on the other hand you have a 120g tank with tons of rock and other fish that get fed and produce enough debri and waste to feed a normal population of pods I would tell you to reconsider the "necessity" of a refugium for pod population replenishment only.

Now, another angle is what someone said before in this thread and that is that he likes to look at the refugium as much as he likes to look at his tank. That is a completely different story and I do repect that. Add to that the question of what do you keep and you have answers that do not apply to a heck of a lot of people.

I still think they are more work than whatever "small" benefit they seem to provide. That is a personal opinion though and I don't expect it to be enforced on others. Great discussion and very good points though. I wished I had followed it more from the begining.

 

[Maxx]

I see your point but then again isn't that why we try to match our return pumps to what we are draining? I mean you don't want to be draining 1000gs and then pumping 3000gs and then trying to turn down the flow right? I don't have a UV in my tank and it's small enough I don't have the major flow issues but I will be setting up my 150g here real soon and may have a difference experience with it.

Yes, and no......

you dont so much match your return pump to what your draining, as opposed to buying an oversized overflow that can handle (drain more) than your pump can push. Make sense? When I get home I can post up an image of how you can reduce the return flow to your tank without causing over pressure to your pump...not to de-rail this thread.....

Alberto, I agree with what your saying. Most folks are using refugiums differently than they were initially intended. Did you go with a refugium in your system? I decided against having one in my system for many of the reasons you listed.

Nick

 

[dgasmd]

Nick:

Nope, I don't have one either.

 

[snobanker]

I have a 55 G refugium on my 10 G reef. The worse part is that the only thing I can get to grow in my reef is a nice healthy clump of macro algae., whereas in my fuge I have softies and LPS doing pretty well.....oh wait... :lol:

Actually I just hooked my fuge a few weeks ago and put in some chaeto last week. I am using it for nutrient export because I seem to have slightly elevated nitrates, but it is now dropping. . I agree with dgasmd in that I am using it as a band aid for the nitrates, and it is kind of an experiment for me, to decide if I want to put one on my new 180 when I get it up and running.

 

[cwrenge]

Good responses. Refugiums can be added at anytime, they can be really simple to complex. Many of us have them and don't even realize it. Overflow boxes can be a refugium, if someone doesn't have space to add one on. It can provide the same benefits of a separate vessel. Toss a little rubble in the overflow box, and it will quickly become inhabited with 'pods of all sorts. On my system, one overflow box is an aiptasia scrubber. Not exactly desired or intentional, but it does serve the purpose of utilizing excess nutrients....and if I harvested the aiptasia, then it would be nutrient export. Here are a few benefits I came up with (most are mentioned in previous posts): 1. When a separate vessel/container is used, depending on size, it will increase water volume and aid in water stability. 2. Filtration via the use of macro algaes, live rock, and/or sand.....even mangroves, xenia, and aiptasia will filter our systems. 3. A place for microorganisms to propagate in. Nice for live foods - especially for fish such as the mandarin. 4. If plants are used, then a lighting cycle opposite the main tank will provide some pH stability during the display tank's nightime hours.

The first step in deciding on how to set-up a refugium would be to determine what you want the refugium to do, and how much maintenance you are willing to perform. For example, the use of caulerpas for nutrient export need to be harvested regularly and properly. This would help reduce the chance of caulerpa going sexual and/or leaking out noxious substances. A refugium specifically for added water volume, biological filtration, and pod propagation (like mine) can simply be a box with live rock and power heads. The maintenance on mine is simply blowing the rocks off and siphoning up the detritus.

We've touched on some benefits and please add more as you see them. Let's talk a little about refugium size (how big should they be in relation to the tank, or does it matter?), placement (different options - some mentioned above - I'll try and dig up some pics), and flow (what should flow be like in a refugium....is it dependent on anything?).

can you describe/diagram, show a pic.... of your Aptasia Scrubber...? and how are you going to ( Ugh..! ) harvest...... your Aptasia...? IMO, any harvesting of aptasia will be an insanely process leading to proliferation.....certainly not birth control.... ? forgive me if you think my thoughts on your "Aptasia Scrubber " are outragious..... cw. :doubt: :doubt: :doubt: