SPS & Refugiums

[JohnV8r]

Can someone please explain to me the logic, science/chemistry behind the notion that refugiums are not a benefit in an SPS tank?

Is there a purported benefit to not having a refugium or is the argument that it is just not necessary?

I'm just trying to understand what is behind the no refugium position.

Thanks in advance.

[Randy Holmes-Farley]

The concern that some folks have is that detritus can settle there and as it is metabolized by various organisms, some of the nitrogen and phosphate will be released back into the water as various nitrogen compounds and phosphate (as it is when fish eat fish foods).

Since some SPS keepers are very focused on low nutrients, they think these inputs may offset advantages that otherwise relate to nutrient export (such as macroalgae growth) or planktonic food production.

[karsseboom]

Refugiums don't really much nutrient export and I don't know why people insist on running them. A tiny little section in your sump with some sand a ball of cheato is really to small in order to be efficient. The sps guys are all about hitting low levels so a lot of times they don't run filter socks and Refugiums. You see a lot of them are bare bottom tanks with top notch equipment and the cleanest looking tanks.

[JohnV8r]

Got it. Thank you!

[mc-cro]

there is nothing wrong with a refugium in the true definition, as a place free from predators.

the problem is that many reefers turn it into a sewer and just let food and detritus sit in there rot. there are no fish in there to eat the waste, so it just sits there and decomposes, releasing unused nutrients into the water.

[JohnV8r]

I started in the hobby back in 1987 and have seen its evolution along the way. I have always tempered my urge to jump on the latest trends without fully understanding them first...and comparing them with my own experiences. I'm not sure whether I would call live rock or the exchange of information created by the internet the most significant change I've seen, but between the two the hobby has shot forward in ways I never thought possible in '87. Maybe dosing Kalk...I don't know; it's all been amazing.

I have run a separate 11" D x15" L x 20" H refugium with a deep sand bed, some live rock rubble, and chaeto for the last 4+ years. My overflow goes into my sump and the return is tee'd so that some return flow hits the fuge. Because of the flow coming after my sump, GFO, carbon, and skimmer, I'm not sure I get a lot of settled detritus in my fuge. Additionally, I have a small army of pods, spaghetti worms, and bristle worms that appear to keep the detritus managed. My fuge is also the source of the pinkest corraline algae that I have - the result of 6500 & 10K flourescent lights vs the 20K MH's in my display tank.

That said, nothing dropped my nitrates and phosphates like vodka dosing. I have had immeasurable nitrates and phosphates since beginning to vodka dose. My system is a net 196 gallons and I only dose .7 ml of vodka daily to get those results. I'm sure the results are from the cumulative impact of everything creating my tank's own personal balance.

I will also say that when I had to move my tank and left it down for almost a year to get rid of some problem aptasia, I was stunned that my tank cycled in about a week by putting some live sand from a "dirty" FOWLER tank in the refugium. Everything else was dry. I put about 6 cups of live sand in my refugium to get that result. I have since looked into products like Dr. Tim's One & Only and get how/why that happened now.

I think for me at this stage I have reached a balance with a refugium that I am comfortable with. I certainly understand the input on the logic for the 'no refugium' movement.

Thanks again.

[mc-cro]

so, just to play a little friendly devils advocate with you

where are your phosphates and nitrates coming from?

[Randy Holmes-Farley]

Refugiums don't really much nutrient export and I don't know why people insist on running them. A tiny little section in your sump with some sand a ball of cheato is really to small in order to be efficient. .

Why do you presume that all refugia are small? Mine are not. In the past they have had a larger surface area than my display aquarium. :)

[Randy Holmes-Farley]

there is nothing wrong with a refugium in the true definition, as a place free from predators.

the problem is that many reefers turn it into a sewer and just let food and detritus sit in there rot. there are no fish in there to eat the waste, so it just sits there and decomposes, releasing unused nutrients into the water.

IMO, that is a widely spoken idea with little data to support it.

A fish that eats food releases nearly all of the eaten phosphate back into the water.

I have no reason to believe that detritus that is consumed by smaller organisms (including bacteria) is any more prone to release the phosphate back into the water than if it were eaten by a fish. :)

[Randy Holmes-Farley]

so, just to play a little friendly devils advocate with you

where are your phosphates and nitrates coming from?

Even if they came from nowhere else and the fish ate all the food, why not from the extcretions of fish? They excrete nearly everything they consume in terms of N and P. People seem to not realize that.

[mc-cro]

okay, but that doesnt change the fact, that if you let everything including the uneaten food, fish poop, and everything else that detritus consists of, just sit there in a big pile that it will not contribute to a nutrient problem.

so, its almost like a sewer septic system in the tank that never get cleaned out?

I understand that fish excrete it most of the nutrients, but at some point you have to clean all the excrement out the tank.

[Ron Reefman]

okay, but that doesnt change the fact, that if you let everything including the uneaten food, fish poop, and everything else that detritus consists of, just sit there in a big pile that it will not contribute to a nutrient problem.

so, its almost like a sewer septic system in the tank that never get cleaned out?

I understand that fish excrete it most of the nutrients, but at some point you have to clean all the excrement out the tank.

A) Inverts (in the DT & the fuge) eat detritus, filter socks capture detritus and a good skimmer pulls lots of organics.
B) My DSB/refugium is about 45g (the entire sump is over 100g).
C) The refugium has macro algae that export some phosphate and nitrate.
D) The refugium is almost as clean as the DT.
E) I have a coil denitrator. IAs a test I didn't do a water change for 12 weeks and I still had zero nitrates and low enough phosphates that only some macro algae grows.

What do you do about all the detritus that settles on your LR and sand bed in your DT?

[JohnV8r]

My nitrates and phosphates unquestionably come from the foods that I feed my fish and corals, and the waste produced thereafter - be it uneaten foods or fish waste. I have pods, shrimp, hermit crabs, spaghetti worms, a diamond goby and nassarius snails that keep the excess food in the display tank to a minimum. There are literally hundreds of copepods visible with a flashlight on my live rock in the display tank at night. The pods scour the live rock. The refugium has no fish or shrimp, but does have the pods, spaghetti worms, and a healthy bristle worm population that weave in & out of the deep sand bed. Add the chaeto and the bacteria populations in the live rock and sand bed, and I'm confident there is no build up of detritus in my refugium. Rather, I think there is an ongoing breakdown/tranformation of the nutrient load that enters the refugium.

As I don't have a nitrate or phosphate problem, the worst case scenario would be that the refugium only provides a safe haven for the reproduction of copepods AND the production of pink corraline algae vs the purple corraline in my display. If that were the only benefit I received from my refugium, that would be enough for me to keep it running.

In my tank, I would say there is no excess detritus building up anywhere. That is why I mentioned that I believe I have achieved the balance I am looking for. While it might make sense for others to remove their refugiums, mine currently provides me with more of a benefit than a negative.

[karsseboom]

Why do you presume that all refugia are small? Mine are not. In the past they have had a larger surface area than my display aquarium. :)

I don't but most people have 12x12 sections in there sump that's used as a refugium. I still don't see te point of a refugium. To grow pods? Will my sps look better with pods? To house fish? Why would I want fish in my sump? If anything I see it doing more harm then good in a full blown ulns sps tank.

[cardiffgiant]

okay, but that doesnt change the fact, that if you let everything including the uneaten food, fish poop, and everything else that detritus consists of, just sit there in a big pile that it will not contribute to a nutrient problem.

so, its almost like a sewer septic system in the tank that never get cleaned out?

I understand that fish excrete it most of the nutrients, but at some point you have to clean all the excrement out the tank.

LOL, then don't do that ;)

The same can be said of any part of your tank. If you don't do anything to maintain your sump, or any type of live rock or sand in your display, then you'll get pile of detritus.

I've got a 30g refugium in my 180g system. It adds some diversity to the tank. I like that it produces live food, and I notice less nuisance algae than when I didn't have one. I run mine bare botton and with a lot of flow.

When I do weekly water changes, I turkey baste rock and sand in my display, then siphon from my the fuge, sump, and frag tank, then rinse chaeto.

[Ron Reefman]

I don't but most people have 12x12 sections in there sump that's used as a refugium. I still don't see te point of a refugium. To grow pods? Will my sps look better with pods? To house fish? Why would I want fish in my sump? If anything I see it doing more harm then good in a full blown ulns sps tank.

Then don't do a refugium! But many of us see it as beneficial and useful, so don't go 'nagging' at us for having them just because you think they are useless. :deadhorse:

[Randy Holmes-Farley]

I don't but most people have 12x12 sections in there sump that's used as a refugium. I still don't see te point of a refugium. To grow pods? Will my sps look better with pods? To house fish? Why would I want fish in my sump? If anything I see it doing more harm then good in a full blown ulns sps tank.

My purpose of my three large refugia is to remove nutrients by growing macroaglae, to provide a place for aerobic bacteria to grow consuming the vinegar I dose, a place for denitrification to take place in the large amounts of live rock present, a place for various organisms to thrive which then get washed into the main tank as food, a place for sponges to grow to help purify the water, and as an emergency place to put things that have some sort of problem in the main tank (like lack of space due to crowding).

[mc-cro]

Then don't do a refugium! But many of us see it as beneficial and useful, so don't go 'nagging' at us for having them just because you think they are useless. :deadhorse:


So, thats your contribution to this discussion?

And what do I do with the detritus in my display......uhhh, blow it off the rocks and siphon it like the everyone else. what do you do?

If a refugium is maintained like the rest of the tank, and periodically cleaned then they can add a benefit. exactly like randy and cardiffgiant are describing.

I am referring to those that believe they never have to be cleaned. I understand the logic, I am one of those former believers. I used to run a 40g fuge on my system. DSB, live rock, macro algea, critters, you name it. I really enjoyed watching the fuge as much as the rest of my tank. I ran that system for about 6yrs. Through the good and the bad.

After taking a step back, doing a lot of research and reading,(away from masses of reef central) I came to realize that in order to have a successful SPS tank, you got to get rid of those nutrients. If your running a softy or lps tank, than a dirty nasty refuge is not going to hurt you.

[reefnut2012]

I ran a DSB refugium on my last 300sps and will definetly be doing it again

[jerpa]

I will say that if your arguing an unkept fuge will contribute to nutrient buildup I will agree. However I would argue that an unkept sump, display tank, skimmer, filter sock, or any other part of your system will do the same. I believe SPS still consume zooplankton so having a denser concentration would be bettwr IME. Growing macroalgae may not be the most efficient way to export nutrients but it accomplishes some. I believe it can be incorporated into a more comprehensive plan and be very beneficial. I may have missed something but i dont see it being widely advocated to never clean your fuge.

[JohnV8r]

@Randy: I don't mean to thread jack my own thread, but - WOW - you really peaked my interest with this comment relating to one of the reasons why you keep three refugia:

to provide a place for aerobic bacteria to grow consuming the vinegar I dose

I dose vodka into my sump because I believed when I began dosing that dilution prior to entrance into my display tank was the most important factor for safe vodka dosing. Your comment about dosing into the refugium has made me question whether I would be better off dosing the vodka into the refugium directly instead of into the sump. Here is a bit of information before you answer that:

1. My refugium is fed from a tee off of my return pump. The refugium technically resides "upstream" from my sump, even though it is fed from water that has travelled through my sump. This old photo from when I set my tank up should help you visualize the flow:

http://www.reefcentral.com/forums/picture.php?albumid=5247&pictureid=36586

2. The refugium has a capacity of 13 gallons. I calculate my net system with live rock at 194 gallons.

3. I currently dose .7 ml of vodka daily, which in concert with other filtration keeps my nitrates and phosphates at immeasurable levels.

4. I currently have a deep sand bed, chaeto, live rock, and lots of pods in my refugium.

5. The refugium is lit 24 hours a day with two 12" T5's (one 6500 & one 10K bulb) and produces a lot of very pink coralline algae that has spread in patches to my display tank.

My question is twofold: 1) Would I benefit from dosing the vodka straight into the refugium where the initial dilution would create a "hot" shot of carbon, potentially creating a more populous area of aerobic bacteria, and 2) would a "hot" shot of carbon or the increase in aerobic bacteria damage the chaeto, pods, or coralline algae?

Feel free to move this question into its own thread to avoid the blending the refugium/no refugium debate with the location of carbon dosing question if you want.

Thanks in advance. It just blows my mind how the discourse on this website can inadvertantly create opportunities to advance the understanding of certain nuances in this hobby!!!

[karsseboom]

Yeah 12 gallons on a 194 gallon system provide very little benefit it the tank if any. All the living creatures in that refugium is just for your own personal experience and may even be more harm then good in a strict ulns sps only tank. Your better off using that space to pack a bigger skimmer or a reactor.

[mc-cro]

I may have missed something but i dont see it being widely advocated to never clean your fuge.

Its not directly intended, but I would have to believe that is what ends up happening in reality. Lets put some common practices together here:

DSB: many people think that you are not suppose to siphon, stir, or disturb a DSB in any manner. Many people put a DSB in the fuge.

live rock rubble: live rock rubble is very beneficial for a number of reasons, but one of its drawbacks, especially in sand, is that it collects detritus

refuge flow rate: commonly the flow is kept extremely low through a fuge.

When you put this together, you have a very low flow area where detritus settles into live rock rubble and the sand bed. since people believe it is a sin to disturb the sand bed, they do not siphon, or move the live rock rubble to get to the detritus. Since they dont siphon or stir, exactly how would they clean it?

It would be interesting to take a poll and see how many people with a small fuge, or heck any fuge, actually take the time to siphon and clean it out every week.

Yes, growing some macro can certainly be a benefit, and a refuge can add some interesting biodiversity, but most, not all, hobbyist, do not take the time to think through the process when they have nutrient problems. Instead they start dosing carbon, adding denitrators, and other stuff to manage the excess nutrients that are still in the system. I personally have found that it is easier to remove excess nutrients rather than trying to manage them.

A skimmer, and harvesting macro does not remove all of the nutrients that you add every day. As Randy mentioned, most of the phosphates go right through the fish and other critters.

A study was done on various skimmer efficiencies, and it was found that even the "best" skimmers only pull roughly 30% of DOC's from the water column of a tank. Cheato and other stuff can only remove so much.

So, that stuff has to come out, right?

[jerpa]

I agree that people spend a lot of time adding equipment to solve problems caused by husbandry practices. Limiting nutrients into the system definitely reduce the need for export but that applies regardless of what method someone uses. You will have the same amount of detritus in a tank with or without a fuge assuming all other things are constant. You have to remove it from somewhere be it the fuge, DT, or sump. If you neglect any of them you will have issues. It may be that SPS tanks forgo the fuge because it's one less thing to clean.

My understanding is that most now believe a DSB should be left undisturbed most of the time but that you should replace a portion of it every year or so. A shallow sandbed should be siphoned or somehow cleaned regularly. I believe this applies no matter where the sandbed is located.

I think the problem lies in the aquarist and not the system. Someone sets up their refuge as an easy way to reduce nutrients, which it does, and never do the required maintenance. At some point it will turn into a nutrient source instead of a sink. I don't think this reduces the effectiveness of refugiums as a whole however.

[mc-cro]

I agree, as a matter of fact, that is what I said at the beginning of this thread, I just didnt expand on it enough I guess

there is nothing wrong with a refugium in the true definition, as a place free from predators.

the problem is that many reefers turn it into a sewer and just let food and detritus sit in there rot. there are no fish in there to eat the waste, so it just sits there and decomposes, releasing unused nutrients into the water.

[jerpa]

No my mistake. I thought you were implying they weren't effective at nutrient export period, not just when neglected.

[Randy Holmes-Farley]

My question is twofold: 1) Would I benefit from dosing the vodka straight into the refugium where the initial dilution would create a "hot" shot of carbon, potentially creating a more populous area of aerobic bacteria, and 2) would a "hot" shot of carbon or the increase in aerobic bacteria damage the chaeto, pods, or coralline algae?


Do you see nuisance bacteria anywhere undesirable? Some folks have such issues, and if so, dosing upstream of where you'd prefer the bacteria to grow is a good idea. I dose upstream from my refugia for that reason, and for the reason that I'd prefer bacteria to consume the vinegar I use rather than the display tank creatures, although I'm sure they get some.

But if you do not see problem bacteria in the main tank, there is no need to worry. :)

[JohnV8r]

Thanks for that! I do not have the bacteria bloom issue that some have. However, once in a blue moon I see a small patch on my sand. I think I'm going to start dosing in my refugium and see if I see any difference.

[Randy Holmes-Farley]

OK, that sounds like a fine plan. :)