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FAQs on Culturing Macro-Algae as a Control

Related FAQs: Algae ControlMarine Algicide Use, Nutrient Limitation, Marine Algae Eaters, Culturing Macro-Algae; Controlling: BGA/Cyano, Red/Encrusting Algae, Green Algae, Brown/Diatom Algae

Related Articles: Algae Control, Marine Maintenance, Nutrient Control and Export, Marine Scavengers, Snails, Hermit Crabs, Mithrax/Emerald Green Crabs, Sea Urchins, Blennies, Algae Filters, Ctenochaetus/Bristle Mouth Tangs, Zebrasoma/Sailfin Tangs, Skimmers, Skimmer Selection, Marine Algae, Coralline Algae, Green Algae, Brown Algae, Blue-Green "Algae"/(Cyanobacteria)Diatoms, Brown Algae

Halimeda ... a good type of algae to grow to out-compete noisome species.

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Marine Aquarium Algae Control

by Robert (Bob) Fenner

Will over-lighting a refugium greatly reduce algae problems   12/15/11
Hi Crew,
<Hey Mark>
I am considering the purchase of a 180 gallon acrylic tank with an internal refugium (dark partition between refugium and display portion of the tank).
 My plan is for a fish only with refugium (FOWR).
I would like to light the refugium horizontally through the acrylic (which if I am correctly reading the response to Light Panels, canopy... design 4/26/08 would be possible).  I read (http://www.sdplastics.com/acryliteliterature/1213FUVtransTB.pdf ) where clear acrylic (ACRYLITE specifically) 1 inch thick only attenuates 0.5% of visible light.  Is this true of acrylic typically used to construct fish tanks? 
<Mmm, no; the loss of useful light is much more... and this is when new, clean... and depends on the fixture/reflector employed... Better to light from the top... with only air twixt the water and light source>
Also, to ensure minimal nuisance algae growth should I have more light in the refugium than I do in the display portion of the system? 
<Mmm, good question (as in I don't know and it makes me wonder re). Again "it depends" on the species of macroalgae employed... Like most photosynthetic life there is low usage, some ideal degree of lighting, then photo-inhibition at some point where the light/ing is too intense...
Besides, the lighting/photonic input may well turn out at times to not be the rate-limiting factor. Often some chemical aspect proves to be limiting...>
When I had a reef tank I had algae issues I couldn't resolve and I think in large part it may have been because there was 5 times as much light in the display tank than there was in the sump/refugium.  I think that if I had decreased the lighting in the display tank and increased the lighting in the sump I may have been able to eventually over come the algae problem.
<Maybe... but there is much more to this equation... best to employ a handful of strategies of limiting and exporting nutrient, predators, competitors to limit nuisance algae proliferation. Such a large, prevalent topic, you can imagine we have much written/discussed and archived on WWM re>
So if I do go through with this project I was thinking of using a bank of 3 40watt (2 tubes each, 4 feet long) fixtures for the refugium (24/7; Caulerpa)
<Mmm (I swear for the last time), I wouldn't use this genus of Green Algae for reasons/rationale gone over and over on WWM. Instead, read here re algae sel. for refugiums: http://www.wetwebmedia.com/refugalgfaq2.htm
 and 1 bank of 60W (6ft long) for the display.  Does this seem like a good starting point?
<Mmm, oops, I guess one more Mmm time... Depends on the size, shape of the refugium... Do read the above, search on WWM re Caulerpa>
 Thank you for your time, Mark
<Cheers, Bob Fenner>

macroalgae vs. microalgae  11/19/10
<Hi Cody.>
Really enjoy your site and have learned a lot!
<Ah, great!>
I have a serious problem with microalgae growth. I've read many of your suggestions and decide to grow some macroalgae to compete with the micro for nutrients. The problem is that the micro begins to cover the macro. I try to wipe or blow the microalgae off with water currents, but I think it causes too much stress on the macroalgae. The first batch of macroalgae died, and I just purchased some more. I was wondering if you had another suggestion on stopping the micro from smothering the macro.
<Ah, well, more information on your system is needed here. My first inclination is to say you do not have sufficient water flow, but email back and let us know the system's specs. Also, I gather you are growing the macro in the display? What macro? Most are far easier to manage in a dedicated refugium.>
The second question is that this microalgae grows very fast when the lights are on, and shrinks very slightly when the lights are off. I was just wondering if this is common with micro, because I've read that lighting
should hinder growth.
<Not necessarily.>
Also, do you think I should reduce the hours of light to help fight the micro or will this ultimately hurt the macro more.
<Again, specs here.>
P.S. I could maybe send pics if that would help, although I'm not great with technology.
<Welcome, Scott V.>

Sump/Fuge issues 11/2/08 I have a 125g reef tank that has been setup for 11 months. It has tons of coralline algae growing on the back and all over the rocks. Parameters are as follows; SG- 1.025, Calcium- 420, KH- 10, Ammonia- 0, Nitrite/Nitrate- 0, Phosphate- 0, Livestock is 2 PJ Cardinals, 1 Midas Blenny, 6 Lyretail Anthias, 1 Dejardin Tang, 1 Yellow Tang, 1 Green Clown Goby, 2 Cleaner Shrimp, 3 Peppermint Shrimp,Various Snails/ Hermits & Corals I have read the FAQ's on sumps/fuges extensively but cannot come to a valid conclusion here, can you help please? <Sure.> My questions are about my so called "fuge". This was my first tank with overflows and a sump, so I had no idea what the difference really was between a sump and a fuge. My LFS told me this was a fuge; dual overflows dumping into 2 socks in the first chamber (the divider does not quite touch the bottom here, about 3" from the bottom), so the water flows under the first divider into a 5" chamber with an egg crate about 4" from the bottom and then into the return (I hope that makes sense). <Yes> My question is, since it has no specific place for sand (between 2 dividers that touch the bottom allowing flow over the top), can I just run Chaeto on the egg crate with no sand? <You can, it does not root into the sand.> I've tried to use Chaeto several times and it just seems to wither away and die after awhile. I was told to keep the light on 24/7 but after reading the FAQ's on your site, I see that this algae seems to like a reverse cycle and that could be a reason why I've never had luck growing this algae. <Chaetomorpha is not an algae to light 24 hrs a day, it appreciates a rest period.> Also, I saw in the FAQ section that it's not a good idea to use a mineral mud in the fuge and then add old snail shells and different size substrates at the same time. I have tried to run a sand bed in this sump, but if it's over 1/4" deep, it just gets broadcast everywhere in the sump due to the dividers not being setup to run a sandbed. <Mud will just be worse. Do consider buying some scrap pieces of plastic form a local distributor and install baffles that will allow you to run the sand.> Also, I seem to have cyano or diatom outbreaks on the sand bed of my main tank frequently, perhaps, due to the sand setup in the sump or the light cycle killing my Chaeto? <Dying Chaeto can pollute, among other things.> My last question is the refugium light is causing all kinds of green and purple looking coralline type algae all over the chamber walls, is this normal? <Yes, no problem, normal growth.> Sorry for the drawn out email and thank you, thank you, thank you for sharing your wisdom! Alan <Welcome, have fun, Scott V.>

Mowing Down Macroalgae?  - 05/23/2006 Hello great reef gurus! I have a question about Udotea (which I have ID'd from photos on your site). I have a 55 gal. reef tank without a sump, approaching 6 years old. Apparently some Udotea hitchhiked into my tank on some new live rock.  I was trying to keep up with picking it off the rock, but lost the battle, and it has now it has spread to other rocks and is starting to take over! <Kind of amazing...this stuff tends to grow slowly in most instances!> I am afraid it will crowd out my corals, plus I really don't like the "new look" of my tank.  My question is (other than WHY people actually want this stuff), is there anything that will eat this?  My Zebrasoma Tang doesn't seem to be dining on it, nor do the Ocellaris Clownfish, Cleaner Shrimp, or snails.  I think I need to do something before my tank looks like a salad garden.  Please advise!! Thanks so much for your expert advise and a wonderful web site! Laura <Well, Laura, this stuff is pretty edible to many herbivores; if the Tang has no interest, you could consider the old fashioned technique of manual extraction...yep- yank the stuff out by hand! Not fun, but much more "reef safe" and selective than other techniques! To be honest, I'd consider the manual extraction technique here. Best of luck! Regards, Scott F.>

Macroalgae warfare 10/05/03 Hi Crew! I am discovering for myself the major downside of grape Caulerpa, <indeed... it has been documented to be perhaps the most noxious of an already very noxious genus of algae> which doesn't seem to be the threat of going sexual, especially since I pull out from my 'fuge a cup or so every few days.   <correct... the threat of "going vegetative" is easily skirted by interrupting the 3-6 month life cycle by regular thinning> It's a weed!  Some other algae species seem to survive (such as feather Caulerpa and sawgrass) but not thrive.  My Gracillaria (Ogo) didn't make it and my C. racemosa also couldn't compete.  The Chaetomorpha ball hasn't grown in over two months!  but I guess it's doing the job of removing nutrients, don't you think? <ahhh... not growing but exporting nutrients? How do you figure? Sounds to me like you've made the mistake of mixing algae that too many folks do. They are very (chemically) competitive with each other. Energies used in warfare could instead be used for good vigor/growth. Please have the discipline to use only one algae species proper in your vegetable filter/refugium. Anthony>

Welcome Back! (Algae control strategy, kudos & input for WWM) I have a 100 gallon acrylic with a T1000 skimmer, 100 lbs. of FFExprees Fiji Live Rock, a 2'' sand bed, and 420 watts of Icecap VHO that are on for 12 hours a day. (Is this about the right photoperiod for algae and mushrooms?)  <Yes... could be extended another couple of hours per day if that fit your schedule> The system pump is rated for 1200 gph and I have two powerheads that rate 395 gph. The tank has been setup for about two months but because of out of town business, I have no fish. However, I do have some mushrooms, a camel shrimp, and feather Caulerpa (about 3/4 of a pound). My alk. is 4.0 and calcium is 380-400. All tests for bad stuff is 0 except for a slight reading of nitrate. <Okay> 1) I am having an awful hair algae problem although I think I might be winning since it's getting a brownish look. It is astounding how fast it grows. . . a true plague. I want to add the salarius fasciatus but I'm going to be out of town for two weeks during the holiday season.  <No worries. Add this fish> Therefore the fish would not have the proper amount of time in quarantine. Would it be okay to freshwater dip with methylene blue and place this guy in the main tank?  <Yes> It would be great if he could keep the algae cropped back while I am vacating. 2) How about dipping inverts? If I exclude the shipping water and rinse the inverts in system water, do they need quarantining? <Mmm, not necessarily... most if appear in good health, can/should be placed directly> 3) To combat this algae problem I have introduced feather caulerpa and halimeda into the main tank, I keep the tank at 76-77 degrees F, and keep alk and calcium high, and I'll add a salarius fasciatus ASAP. Would you suggest anything else not mentioned on WWM other than a refugium? <Not enough data to suggest more.> 4) One final question: An LFS owner told me (today) that the only reason to quarantine was to protect the critters that you already have from becoming infected with a parasite from a new addition. <Mmm, what about granting the new livestock a rest period? A bit of hardening on their own... a chance for you to observe them?> He said that if no fish are present (like my tank) then there is no reason to quarantine since overcrowding is not a concern. From what I know, this argument just doesn't ring true. I know that eventually I will probably need to get a balance between parasites and hosts (add cleaner shrimps etc.), but isn't it silly to risk infecting my tank with the FIRST FISH? <You are correct... right to question any/all "authority"> Bob, I know this FAQ writing is probably difficult for you to maintain on a daily basis but it is truly a great feature of this site; and because the information changes daily, there is always something new to read.  <Thank you for this> That is the biggest problem with most fishy sites. The information gets loaded onto the site, and sits there year after year with no updates.  <Is this "possible"... that is, how could any field hope to stay abreast of topics, insights, input w/o constant renewal?> Aquarium Frontiers was a fantastic publication IMO but at this point it's a dead site that is quickly getting outdated. Thanks for the effort and hard work!! David Dowless <You are welcome my friend. Thank you for your input, addition. Bob Fenner>

Green seaweed research questions (and useful, scientific input!) Hi Bob, I found your address at the WetWeb site and thought I'd contact you directly. Hope you don't mind. <Not at all> I'm a bio professor/researcher who studies the reproductive behavior of tropical green algae in their natural environments (Halimeda, Caulerpa, Penicillus, etc). I notice a fair number of posts to aquarium sites that have to do with "green clouds", "white" or "dying seaweeds", etc. and recognize (as you do) that most of this relates to the sexual reproduction of these seaweeds... a 24 hour conversion from sterile to fertile condition, followed by explosive gamete release at dawn and immediate death of the "parent". <Yes.> My research explores the consequences of these reproductive events on coral reefs (mostly Caribbean, though I'm currently on sabbatical in Guam). I'm particularly interested in what induces a seaweed to become fertile, since we often find hundred to thousands of algae on a reef (but never all of them) becoming simultaneously fertile... not only is the ensuing bout of sex the next morning a spectacular visual phenominon.. the subsequent death of so many "adult" seaweeds has important ecological implications for the reef community as a whole. <Agreed> I notice from various posts within the aquarium trade that lights, chemistry, temperature, stress, etc, etc, are implicated in the onset or prevention of reproduction by green seaweeds in aquaria. Do you know of any formal treatment of this idea...  <No... unfortunately seem to be entirely anecdotal accounts... of "stress", change that bring on these events.> or is it just a hodgepodge of observations thrown out over time? I notice you reference "24 h" lighting as a preventative and I've seen reference to blue lights, or non-blue lights (can't remember which) having similar effects. If you're interested, I'd love to pick your brain about this... or you can sic me on someone else. <Very glad to be of assistance.> If interested, you can also learn more about my research on seaweeds by visiting: http://lclark.edu/~clifton/Algae.html <Thank you much for this reference. Will post to our sites (WetWebMedia)for hobbyist perusal> Thanks for your time... I hope to hear back from you. Ken Clifton <Sorry for the delay in response. Have been on a liveaboard... in the Bahamas. Be chatting, Bob Fenner>

algae is everywhere Hi Bob: <Actually, Lorenzo Gonzalez, standing in for Bob-in-Singapore> My husband Bob and I have had a 30 gallon mini reef tank. It has been standing for just over 3 years. We have a purple tang, a percula clown, a cleaner shrimp, a cowry snail. We recently lost our flame angel and gobi (w/in the last year due to moving & we believe age). We also have 3 strip lights consisting of: 2 36" 50/50 bulbs; and 1 24" actinic bulb. The lights stay on for about 10-12 hours with the actinic on one hour past the 50/50's, which we believe is too long. We have all the classic types of algae; brown, red, some hair, coraline, somesort of brownish film algae, and somesort of algae that looks like a pine bush.  <The one you're missing is caulerpa, which is a great competitor for the nutrients that keep the 'undesirable' algae flourishing, and is much nicer to look at, and far easier to prune and throw away! Your photo-period sounds fine - be sure you don't have stray/occasional/random sun hitting the tank - and that the bulbs are all replaced (one at a time over 3-5 days) every 12-14 months, working or not.> We usually keep the traditional snails & blue legged crabs. We have recently purchased about 25 red legged crabs, 15 blue legged crabs, 2 emerald crabs, 20 Mexican turbo snails and 2 bristle stars.  <Wow! Quite the clean-up-crew-package-deal, sounds like!> We would like you opinion on our situation to better control the tank and it's algae. Our filter system consists off a 304 biological filter and a skilter 400.  <That sounds fine for a 30 gallon. Keep the air-water 'reaction chamber' of the skilter religiously clean for maximum effect.> Lastly, what is your opinion of the bristle stars. Can they harm our anemones or feather dusters? <No. They'll be fine. And in fact, all the stirring, and munching of all these new critters will likely clobber your algae problems... but watch carefully for dead newbies! Remove any snails that don't move for several hours, if they don't 'latch on' and move around if you pick them up and place them on a rock. And any snails that fall down in the sand should be righted on a rock as SOON as you notice, or the blue-legged hermits will attack them for their real-estate!> Tanks a lot Jen & Bob <Welcomes a lot! -Lorenzo>

Question: I have a green algae that is growing on the glass of my 85 gallon Hex tank. It is 3 years old, has a sump filter system with a skimmer inside. I have a 175 watt 5500K Metal halide with reflector installed along with an attinic blue flourescent bulb. I have been using some calcium blocks from a local reseller and I cam not experiencing any coralline algae growth anywhere. I have 2 tangs (Chervron and Yellow) a Sleeper goby a niger trigger a neon damsel and a rock beauty angel. They are doing great.

I have about 65 lbs of live rock and it too is covered in the same green algae any new peace after a week or so loses its beautiful colors and is covered with the same algae, and I am not sure how to start the coralline algae growth. My fish prevent any heavy algae growth. Can you help me, Please.....

New Print and eBook on Amazon

Marine Aquarium Algae Control

by Robert (Bob) Fenner

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