FAQs about Green Macro-Algae 1 Related Articles: Embracing Biodiversity, Green Algae By Mark E. Evans, Green Algae,  Avoiding Algae Problems in Marine System, 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,  Related FAQs: Caulerpas, Green Macro-Algae 2,  Green Macro Algae 3,  Green Macro-Algae 4, Chlorophyte Identification, Chlorophyte Behavior, Chlorophyte Compatibility/Control, Chlorophyte Selection, Chlorophyte Systems, Chlorophyte Nutrition, Chlorophyte Disease, Chlorophyte Reproduction/Propagation, Marine Algae ID 1, Marine Algae ID 2, Marine Algae Control FAQs II, Marine Algaecide Use, Nutrient Limitation, Marine Algae Eaters, Culturing Macro-Algae; Controlling: BGA/Cyano, Red/Encrusting Algae, Green Algae, Brown/Diatom Algae,  Friends and Foes: Greens can be both; a Caulerpa stand and a Valonia ventricosa single cell in Belize.

Green Algae Greetings! <<And greetings to you - JasonC here...>> First let me thank you for the always great advice and prompt responses. I know I really appreciate it a lot. I read the FAQ's almost daily to try and increase what little knowledge I have :-). I have 1 question for you. <<Go for it.>> Here is my setup: 75 gallon tank Emperor 404 with 3 carbon packs and 1 Nitra Zorb 1 Skilter 250 retrofitted with limewood stone for protein skimming 2 oscillating 214 powerheads 70+ lbs live rock 80 lbs live sand 6 green Chromis 1 striped damsel 1 dragon goby 1 spotted cheek tang (related to Kole tang) 1 Pacific Blue tang 3 turbo snails 1 sand sifting starfish <10 small hermit crabs 1 small Xenia coral (Waving hand) 1 group (20-25) green button polyps 1 40w actinic (sunrise sunset) 2x 110 10k Aquasun VHO and 1 110 watt actinic (10 hours on @ 370 watts total) My question is this. I keep getting a "film" of some sort of green algae on my glass. When I clean it with the magnetic cleaner, it looks "dusty" on the inside. I could do this once every two hours and still not keep up. I have been told by my LFS that it is a "phase". I don't overfeed and all my readings are fine (78 degrees, 0 ammonia, 0 nitrate, 5 nitrite, 8.3-8.4 PH) with weekly 8-10 gallon water changes. Is there anything I can do to alleviate this or am I just going to have to clean my tank forever? <<I would agree with your LFS and say this is a phase - could be the tank is getting some sun during the day? This is often a factor... but yes, glass cleaning is part of the normal maintenance.>> And everyone in my tank gets along GREAT!! <<Glad to hear it.>> Thanks again for all the help! Richard Riedling II <<Cheers, J -- >>

Green Algae (Take II) Greetings! <and salutations to you> First let me thank you for the always great advice and prompt responses. I know I really appreciate it a lot. I read the FAQ's almost daily to try and increase what little knowledge I have :-).  <and share your knowledge in kind> I have 1 question for you. Here is my setup: 75 gallon tank Emperor 404 with 3 carbon packs and 1 Nitra Zorb 1 Skilter 250 retrofitted with limewood stone for protein skimming 2 oscillating 214 powerheads 70+ lbs live rock 80 lbs live sand 6 green Chromis 1 striped damsel 1 dragon goby 1 spotted cheek tang (related to Kole tang) 1 Pacific Blue tang 3 turbo snails 1 sand sifting starfish <10 small hermit crabs 1 small Xenia coral (Waving hand) 1 group (20-25) green button polyps 1 40w actinic (sunrise sunset) 2x 110 10k Aquasun VHO and 1 110 watt actinic (10 hours on @ 370 watts total) My question is this. I keep getting a "film" of some sort of green algae on my glass. When I clean it with the magnetic cleaner, it looks "dusty" on the inside. I could do this once every two hours and still not keep up. I have been told by my LFS that it is a "phase".  <if the tank is less than 4 months old then the diagnosis is not only possible but likely! And regardless of the age of the tank, any such nuisance algae can be easily starved into oblivion with aggressive protein skimming. If you adjust your skimmer to produce daily consistent dark skimmate, your algae will disappear in 2-6 weeks> I don't overfeed and all my readings are fine (78 degrees, 0 ammonia, 0 nitrate, 5 nitrite, 8.3-8.4 PH) with weekly 8-10 gallon water changes. Is there anything I can do to alleviate this or am I just going to have to clean my tank forever? And everyone in my tank gets along GREAT!! Thanks again for all the help! Richard Riedling II <best regards, Anthony>

Algal succession Hi again, <howdy> Suddenly my two month old tank is sprouting bright green spots on a lot of the rocks and coral skeletons. Any idea what they are and whether they are good or bad?  <green microalgae... quite natural in the process of algal succession (brown algae is waning I assume)> They are actually a beautiful, brilliant color so I'd hate to hear that they are a nasty thing that I must eradicate. <if you control nutrients in the tank you can enjoy a nice luxurious growth of it without it taking over> Ana M. Saavedra <best regards, Anthony>

Algae information Hi Didilly Ho Neighbor, I have located some pictures and a name for a plant/algae that may be residing on some of my live rock (if I have identified it correctly). It goes by the scientific name of Acetabularia ryukyuensis. I used that name on the WetWebMedia search but had no results. Would you be able to point me toward some information on this type of life? Thanks in advance, <Mmm, well, do know the genus (from the western Atlantic species)... this Japanese one I have no experience or knowledge of... a search: http://research.kahaku.go.jp/botany/seaweeds/GreenAlgae/kasanori.html might be worthwhile. Bob Fenner> Andy Weaver

Clownfish and Bubbles! I have an 80 gallon reef taken that has been set up for almost two years now. One of the occupants of almost all that time is a Sebae Anemone. Actually I believe it is a Long Tentacled Anemone that was misidentified by the internet store I bought it from. Several months ago, I added two tank raised Percula's. Up until a few days ago, the Percula's could not have cared less about the anemone, which has grown to a substantial size. Recently though, they're wilder instincts have kicked in, and now they will not come out of the Anemone, even to eat! <Sometimes it takes a while for them to take to an anemone.> Additionally, there is some nipping and chasing going on between them. <Probably working out who is who in their relationship. Clownfish developed into males and females. The females grow larger and are generally the meaner ones.> Anything I can do to encourage them to eat? <Offer a greater variety of foods, but no real worries. They will not let themselves starve to death.> Will they be able to share the one Anemone? <If they become a pair, yes.> On a fairly consistent basis I have bubbles that grow from the rock. Not your ordinary everyday air bubble. Rather bubbles that start the size of a small marble and grow to about golf ball size. They are greenish, almost like algae was growing on them. <They are in fact algae themselves.> I opened on once, and found it to be empty. <That is what you thought. The inside of bubble algae is filled with hundreds of spores for reproduction.> The material it was made of had the consistency of cellophane, though apparently when they pop either something eats them or they dissolve as I have never found one just lying on the bottom. Any idea's what this could be. <It sounds like bubble algae. Please search www.WetWebMedia.com for bubble algae or Valonia.> Your consideration is appreciated. <Have a nice night. -Steven Pro>

Bubble Algae, Wanted or Not? Bob, I recently got back from my local pet shop. He had a large cluster of what he called bubble algae in his tank. I thought it was neat looking. I asked him if their would be a problem with this stuff taking over my tank. He said no, that he thought it was cool looking stuff also. <I do think some of them are neat, too. In particular, the one referred to a "dead sailor's eyeball" is actually attractive, IMO. It is larger than most other types, about marble size, and has a gray green metallic appearance. But, like any other algae, it can become a problem is given conditions where it will grow out of control.> He gave me some to take home. The more I read on WWM I don't know if this was a mistake? <If your system is well run, low nutrients, the bubble algae will die off in time. Otherwise, it can reproduce and become a problem for corals. No real harm to fishes.> It looks allot like Grape Caulerpa, is their a good picture on WWM to compare? <Do try the Google feature searching for bubble algae/Valonia.> Should I get rid of this stuff ASAP? <It will get rid of itself if your tank and your tank have proper husbandry.> Thanks for your input, Jeff <You are welcome. -Steven Pro>

Halimeda Cycle Oh Wise Guys! <<and hello to you.>> I had an interesting occurrence this past weekend that I'd like to understand. I have a lot of Halimeda in my 100gal tank and about half of it went into the end of its life bloom (my poor term). You know, at first it turns white with tiny green spots or spores on the outer most leaves, then it releases these about a day later into the water causing a very cloudy condition. The interesting part was not the bloom - as I've seen it before - but the apparent suffering caused to one of two yellow-tailed blue damsels. For a day or two he showed signs of poor water chemistry. He was hiding, not eating or seen resting on the bottom. I immediately did a 5 gal water change. Then followed it up a day later with another 5 gallons. The fish seemed to recover quickly. What caused the stress? The Foxface, cinnamon clown, and yellow tang were also unaffected as was the red brain coral. <<Very hard to say specifically without some chemical analysis. Did you check any of the normal parameters... perhaps nitrates skyrocketed... hard to state at this point what the problem was exactly besides the obvious: something from the algae bloom/die-off.>> P.S. If I were to add one more way cool fish what would you suggest? <<Oh... the list is too long. Do check through the pages in WetWebMedia. Many, many to choose from.>> P.P.S. Finally bought Mr. Fenner's book at Scripps Aquarium here locally. Boy, I didn't expect so many beautiful photos. It can be a 'coffee table' book as well as a good reference. <<Indeed.>> Also, what happened to the Rabbitfishes (Foxface) section? <<If you look in WetWebMedia, you'll see these fish covered in the same section as the Tang/Surgeonfish.>> David <<Cheers, J -- >>

Maidens Hair is disintegrating Hi there, oh sea gods. <more like sea walruses... especially the slobbering part> Quick question: My maidens hair seems to be bleaching out from paler green to brown, especially at the tips, and thinning on the rock. I have a 33Long and it is about 8 inches from the PC 220W hood. Stats are OKish on the tank... calcium about 400, ammonia a little high after a cleaner bio load and some more live sand (about 15) nitrate about 2.5, nitrite 0, ph 8.4 alk norm phosphate 0. Any ideas? I love the stuff. Should it be closer to the hood? -Brooke in Boston <such algae are categorically difficult to keep. Lighting is likely not the issue here. They may need more nutrients and probably need a lot more current. Perhaps a dynamic refugium would suit this species better. Anthony>

Re: Maidens Hair is disintegrating ---Thanks :( I feel like a loser. How will I get to keep actual animals alive if I can't even keep alive algae? Oh well.... I'll keep at it. <no worries at all my friend! Some of these decorative alga are actually very difficult to keep...they are collected in areas that would be impossible or undesirable to replicate in aquaria. Trudge on! :) Anthony>

Feather dusters, hitchhiker id, bubble spewing powerhead One of the Shaving Brushes that I got in a mail order Thursday has a clump/blob/coil of yellow/orangish stuff that looks like a string of pearls. It is hard to the touch and is imbedded at the base of the green, right above the calcareous tube. The "pearls" are about 2-3 mm in diameter with an equal sized space between each and the next one and the "pearls" are held together with a strand of the same color. Do you have any idea what this might be? I have no digital camera or I would send a photo. <Could be a sex product or colonial invertebrate species of some sort...> Please advise about placement of feather dusters. I put them in the tank and this a.m. they are all laying down, rather than standing up, but are all open. One spewed out a bunch of cloudy puffs this morning. It didn't leave any mucus trails, just cloudy puffs, 6 or 7 of them. Does this signal trouble? <Not necessarily... but do take a look at the images on WetWebMedia.com re these polychaete worms... http://www.wetwebmedia.com/feather.htm should not be just laid on the bottom of your tank> Finally, billions of bitty bubbles are shooting out of my fully submerged, 1 week old, AquaClear 402 powerhead. It is located in the back right corner of my 46 gal bow front, below and slightly to the right of my SeaClone protein skimmer. In the back left I have an AquaClear 300 hang on filter. I turned off the protein skimmer and the powerhead is still shooting out tiny air bubbles is spurts, about every 10 seconds. I have no coral - unless it is slowly developing on the LR, but I haven't seen any yet. Do I need to stop this bubble shooting? If so, how do you suggest? <Please use the search feature... on the bottom of the homepage of WWM: http://www.wetwebmedia.com/ inputting your search terms... and read through the many FAQs re "tiny bubbles" and your gear. Bob Fenner> TIA for your help. Jeanne

Shaving Brush Problems <<Bob is away diving, JasonC at your service...>> Bob, I'm having a hard time keeping and growing 5 Shaving Brushes in my 50 gallon reef tank, which is being setup for over three years with no major problems. The problem I'm having is that any new growth, when it gets to about 2" to 3" it turns brown and dies. My calcium level is find, as well as Iron and iodine. I haven't been able to find any kind of info on the requirements of this type of macro algae or the proper maintenance. Any help or recommendations will be greatly appreciated. <<I've had no experience with these myself, and given your report on the tank conditions, I would suggest you post this question on the discussion forum. Bob won't be back for another week and there are some really skilled aquarists who lurk on that board. You may find someone who knows what this means. http://talk.wetwebfotos.com/ If that fails, Bob should be returning 12/7. Cheers, J -- >>

Aiptasia, Halimeda Hi Bob, How are you? I was doing just fine myself until I found my first Aiptasia Anemone. Them there was three....eight....you get the picture. I've read your posted information through but still need a little help with a predator for my new specimen. The animal I would like is the Peppermint shrimp. You say, as do some of the queries I read that may eat other corals or stinging creatures when the Aiptasia is gone, or even along the way. John H. Tullock says numerous times in his book "Reef Aquariums" that the Peppermint shrimp is a great choice for reef aquariums due to their propensity to spawn. I don't expect to rear any of them, but the plankton would be nice. This seems very appealing to me, but not at the expense of my corals. Do they have any preference in corals once the Aiptasia is gone? I have a Torch, Slipper, Candycane (2), and Branched Hammer? <Often the Euphylliids are preferred... you can generally see this developing before much damage occurs> From your site I gather you would choose the Berghia Nudibranch. You also suggest removing it once the Aiptasia is gone. How long will it survive after feeding? <For a few weeks after apparently all Aiptasia are no longer apparent... if left in will just "disappear"... die from starvation> The reason I ask this is I wouldn't want to get rid of it too soon only to have the pest return or be rediscovered. On an unrelated topic, how do you feel about calcareous alga such as members from the genus Halimeda. They seem to be readily available and from most accounts are hardy. What would be the potential problems associated with them?  <Competition for biominerals, alkaline reserve mainly> I do successfully keep a few specimens of Caulerpa with no problems in a refugium. I prune them regularly and relocate it to display tank for Tang food. Will my Tang consume the Halimeda? <Not much if it is very calcified... but some likely. Bob Fenner>

Culturing Halimeda Dear Bob, Steve, or Anthony: <Anthony and at least two of my personalities here...Bob and Steve unavailable> I emailed you a couple of days ago regarding reducing the sand bed depth in my 150gal FOWLR system. I have already began the reduction and am pleased to report everything seems ok! Thanks for the good advice! <ducky...just ducky> I was wondering if I could pick your brain on one other item. I have a nice stand of Halimeda on one side of the tank, and I was wondering if it is possible to propagate this macroalgae by "cuttings". <not so literally, although reproduces sexually with ease once mature. best bets are rooting in sand> Or- is there a better way? If Halimeda can be propagated in this manner, do the "cuttings" need to be secured to a rock or other substrate in order to grow? <see above... although better to let it mature and reproduce naturally. A sexual event is indicated by a sudden "bleaching" of the colony leaving behind a bespeckled (with green) white plant that soon dissolves. "Babies" pop up everywhere afterwards within weeks to months. Skim well during the event> I'd appreciate any tips/comments/warnings you might have on propagating this macroalgae. <of course...you could always try good wine and Luther Vandross music> Thanks! Scott F <you are quite welcome. Anthony>

Halimeda and Calcium Happy Holidays! Through help from your website I feel I have made great progress in understanding the chemistry of my tank. Lately I have been trying to get a grip on the CO2, bicarbonate, buffering action which is a very interesting dance.  <Well put> I purchased alkalinity and Ca test kits to see where the tank is situated in the continuum. <Ah, even better> My alkalinity was a paltry 80 which I subsequently boosted to 180ish with NA bicarb. The Ca was dreadfully low too at about 150 ppm. Subsequently I purchased ESV 2 part solutions to try and boost the Ca. I add it in the mornings as directed. It has been about 3 weeks and the concentration hasn't budged. I believe the reason is the calcareous algae. <Likely> I have a 100gal tank with a generous (2-3 cu ft volume) amount of Halimeda. I believe it is absorbing it soon after it becomes available. I don't believe it's precipitating but my pH does reach 8.4-8.6 by the end of the day. How would one know if it's precipitating? <Mmm, you would likely see (yes, that much) the "powder" on the surface of your substrate, rock...> Short of buying a coral dissolver (Ca reactor) I believe my best courses of action would be to cut back the Halimeda and/or increase the supplement and watch the parameters. <Yes... I would try a bit of both> I'd prefer the former over the latter. What would you suggest? The only other consumer of Ca is a Trachyphyllia geoffroyi. It's been in the tank 2 months and seems content. Should I be concerned about its well-being under chronically low Ca concentrations? <Not so much... it has adapted well-enough to your conditions... and has other mechanisms for utilizing food, alkaline and biomineral sources (the last two from other than the water)> P.S. I've gone night diving in my tank! I mean after the lights have gone off and I am feeding the Trachyphyllia geoffroyi the night critters come out. It's a whole different perspective that I recommend others to try. Thanks again and Happy New Year!! <Yes! Be chatting my friend. Bob Fenner> David A. Bidwell

Algae like a bristle Hello, Bob Over the past month, an algae I've never seen before has spread all over my tank. Please see a picture, which I send you. Do you know these algae? They look like a bristle, they are hard, sharp and brown and purplish red. They covered many places on my rocks. My Yellow Tang nibbles them a little. Are they good or bad? <Does look like, description fits the nuisance Greens of the genus Bryopsis: http://www.wetwebmedia.com/greenalg.htm Please read here and the links, FAQs about this area on WetWebMedia.com Not toxic, problematical other than intrusive, undesirable from the standpoint of taking up space, light, nutrients you might want to provide to other life forms> I would be very thankful for your answer. I wish you Happy New Year. With regards Krzysztof Tryc, Poland, Warsaw <Thank you my friend. And to you, yours. Bob Fenner>

Algae ID Hello Mr. Fenner. I hope you are having a great holiday season. I wanted to write (though I know you get so many letters and it is impossible to remember them all) and give you an update on my Neon Goby who is in quarantine for ick along with my green Chromis and mated clowns. Their two weeks of copper is up today. I'm going to run a Poly filter in there and some activated carbon as well. They now have three more weeks to go. My Goby looks awful. His black body is rather gray and his blue stripe is very faded. He has tannish splotches all over him. I am guessing that it is just scars. <Sort of... distress coloration, markings from treatment> He is eating well and swimming around when I am not in the room. :) I have one question to ask of you. I hope that is OK. I have an algae growth happening in the main tank. I'm not sure what it is. I have an attachment of a picture in this email. The pic doesn't show the color very well. It's kind of a yellowish brown. <I see it... looks like some sort of filamentous green... kind of bleached out> I do have a refugium that I started a few weeks ago (20gallons-main tank 75gallon) that has a 3" sand bed, Caulerpa and live rock. Light on 24/7 64watt outdoor HD light. Is this just part of the tank recycling, or is a bad guy like hair algae that I need to go after? <Just a temporary nuisance. I wouldn't sweat it> Are you able to say what it might be? <Mmm, not any more than I have. Do you have a microscope?> Thank you so much for your help!!! I am reading all of your algae links right now, but it's hard not knowing what kind of algae I have. :) J. <Concentrate on any general algae situation, though this is most certainly a Chlorophyte... Bob Fenner>

Major Reef Tank Problem (green hair algae) Dear Bob: I haven't communicated with you for a while. I hope everything is well with you. <Yes. Thank you> Bob, I am trying not to become overly depressed about my 92 gallon reef set-up. I've got an out of control hair/turf algae problem that I cannot pinpoint the cause. Here are some facts: <Not to worry... many causes, cures... we can solve this one> -My tank is 15 months old -90 lbs of live rock -20 gallon sump refugium with housing some Caulerpa algae lighted by a 65 watt LOA Flourex light about 16 hours/day -Euroreef skimmer - MAG 7 return pump -3 internal powerheads -about 2 inches of aragonite sand. Particle size in between crushed coral and oolite sand -low bioload, i.e., 3 fish, cleanup crew, cleaner shrimp, 4 soft corals, 2 LPS corals, mushrooms, button polyps -top off reservoir filled with Tap Water Purifier water -0 nitrates reading -0 phosphate reading -2.5 mg/l alkalinity <Mmm, this is a bit low...> -450 ppm calcium -IceCap 660 VHO lamp system - 1 95 watt actinic blue URI lamp, 1 95 watt white 50/50 URI lamp, 1 95 watt Aquasun URI lamp and 1 75 watt actinic blue URI lamp Turf/hair algae is completely overrunning my tank. It is growing in between my candy cane coral, on every rock, some of it is up to 1 inch in length, some even on sand, consuming almost all of my button polyps, etc. For about 4 weeks now I have been scrubbing rocks and trying pull out this algae, scooping it out with a net. In addition I have been doing 20% water changes every two weeks. Last week, I even took out half of my rock and scrubbed it in a separate container, but it is now growing again on it. I have had carbon in the sump now for about a week, and also Marc Weiss' new Phosphate/Silicate Magnet product in there for 3 days now. <Get rid of this product> I believe my problem may have begun when I decided I needed to start replacing my lamps since it had been 1 year since I purchased them. I first changed the Aquasun, and noticed within about a week that algae was starting to grow on the rocks below this lamp. I changed the remaining lamps, each being changed about every 2 weeks. <Mmm, maybe a source of stimulation... you know now that you want to cycle the lamps in/out on an "effective life span cycle"> Bob, I am so frustrated. I have had no losses of life due to bad water conditions until now - my normally perfectly healthy 8 month old Yellowhead Jawfish I believe got so stressed out from my rock scrubbing and turkey baster blowing that he stopped eating and died, and a new Foxface I got to help with algae control never adjusted and died in a week. Your input would be greatly appreciated, as I am baffled. <You have nice gear, seem quite aware of what is going on (you know what you know) re your system. I would take some simple, plain steps at this point to return your system to "center". As easy as it may seem, raising your alkalinity is paramount to your success here. You don't mention how you raise your calcium, but I would look into two part additives, supplements that contain calcium chloride, and use a modicum of simple baking soda (sodium bicarbonate), a few teaspoons dissolved in system water per day, poured in about the surface... and measure in the AM to see if you're able to boost alkalinity in this way. In addition I would add some of my favorite algae eaters: One or two specimens of Salarias fasciatus or Atrosalarias sp. blennies.  Do get/use a phosphate test kit... this source of rate-limiting nutrient may be playing a pivotal role here... And please read through the many FAQs, articles on "marine algae", "control" posted on the WWM site starting here: http://www.wetwebmedia.com/algaeconMar.htm We can/could talk over the implementation of a calcium reactor (a carbon dioxide infusion type), getting a reverse osmosis unit for your new water use (in place of the TWP)... but that can/will come later. Try to read over the links where I've sent you, and prepare for the changes suggested. In a few weeks, the pest hair algae problem will be in decline. Bob Fenner> Sorry for the long dissertation, but I wanted to give you as much information as possible. John

Re: Major Reef Tank Problem Thank you for your reply Bob. I did forget to mention that my open brain coral is also not expanding like it normally does, and my pagoda cup coral has not been extending any of it's polyps for about 1 week now. I have been testing for phosphates (SERA test kit) and my readings are nil. I'll take out the Marc Weiss product at your suggestion, but should I keep the carbon in? <Yes> Also, I am using Kent Marine's 2 part alk/calcium system, and dripping granular alkalinity or calcium (Kent) into my sump if these levels have been low. I do agree my system is not "centered" like you stated. Before all of this disrupt, it seems like all I needed to do was add my 2 part solutions and everything was fine. Another additional step I have taken lately has been adding magnesium because my test results showed lower levels. Finally, I forgot to mention that I am noticing a kind of film with small particles that has constantly remained on the water surface. <From the additives... no big deal... can be lifted off with a clean, unscented paper towel as a "wick"> Again, thanks so much for your advice. I do hope you can help get my tank out of this funk so I can really enjoy this great hobby again. <I'll be here to help if I can. Bob Fenner> John

Re: Major Reef Tank Problem Thanks once again, Bob. Last question (I think, at least for now!) - do you think I should temporarily reduce the photoperiod? I did this for about 2 weeks (about 4 hrs/day), but I am afraid that my photosynthetic corals may not want this shortened period any longer. <Agreed. I would not shorten, alter your photoperiod. Bob Fenner>

Algae Farm Hi Bob, My quarantine tank is a simple 10 gallon, $30 Wal-Mart deal with a cheap filter and a very basic light hood. It works fine to quarantine the new fish and to administer some medication when needed. It seems like a waste to just have it sitting there empty when its not needed as a quarantine tank (which means its empty most of the time). So, I was thinking of turning it into a algae aqua farm for my tangs, but wanted to bounce the concept off from you first. <Good idea... maybe it can/could be tied in with your main system as a sump/refugium with slow flow rate... and the circulation to/from cut off if/when you need/want to utilize it for other purposes?> I was thinking of filling it with water, having no substrate in it like a normal quarantine tank (and for when it is needed as a quarantine tank), and keeping the filter going as a basic water mover. I was thinking of then taking a couple of chunks of live rock / base rock from the display tank and tossing them in, along with a macro-algae encrusted piece of rock from the LFS. I am thinking that the algae should grow like wild fire with the hood on 24 / 7 -- I could then toss the rocks back and forth from the display tank for the tangs to have fresh food. What do you think? Am I missing anything? What could be added to make it better; make the algae grow faster? <Having some water from your main system go through would supply needed/desired nutrients, and in turn modify your water chemistry to the benefit of the main system. Please read here: http://www.wetwebmedia.com/refugium.htm and the FAQs beyond.> Thanks for the input, as always! Dale. <Be chatting. Bob Fenner>

Tangs & Algae Mr. Fenner, I haven written to you in the past and am in need of your advice again. I might be answering my own questions, so maybe you can just tell me if I am on the right track? <Will do so> I have a 75 gallon Reef just starting out. I have a sump (bio-balls), 85 pounds live rock and a 2" LS, crushed coral bed. Power Compact lighting 384 watts. 4 powerheads. Berlin Skimmer. Ammonia 0 Nitrite 0 Nitrate 10ppm pH 8.4 Ca 430 Alk 1.7mill (working on raising) <Do so.> Temp. 79 1 Yellow tang, 3 green Chromis, 2 cleaner shrimp, 5 Astrea snails, 4 hermit crabs, feather Caulerpa (a spattering,) <Will be more with increasing alkalinity> & a torch coral. My problem is, what else, algae. I had at one time diatom covering my rocks and sand, and green film covering all over my glass (both cleaned each day.) When I added my torch coral and the small amount of Caulerpa, (my tang ate 3/4 of it in two days, leaving only a bit of feather. did have grape, & cup) the green algae disappeared from the glass and the diatom on the bottom cleared some. It's taking up nutrients I believe. <Yes... and you might want to try Halimeda spp... not quite as palatable and do much the same jobs> My problem is that I have a film of this gray-green stuff floating on top of my water, on the right side. Perhaps my powerhead placement is not moving it to the overflow box?  <Possibly... or you might need more surface disruption, skimming from other influences> I tried to mess around with that but to no avail. Next problem is that I have no room for a separate refugium. <No where? Even about the system?> I have a Del-Ray filter and am all thumbs. I have no idea what's so ever on how to convert that to a refugium. I looking all over your links and the web for a DIY plan. No help there.  <Look on OzReef: http://www.ozreef.org/ and beyond on their links> So I thought I would grow macroalgae in the main tank. That was mostly a bust because my tang realized he had a smorgasbord before him. Just a little feather left. Since I do not know how to turn the del-ray system to a refugium, could you tell me what would be the best choice for macroalgae that my tang would turn it's nose up at? <See the macro-algae information areas on WetWebMedia> Last but not least is that I add B-Ionic to my water once a week to buffer my Alk & Ca, 20 mill each, and the alk has been added more often. Try as I might I cannot get my Alk up. <Switch to other products, or try supplementing with more carbonate, bicarbonate... in the shorter term, simple baking soda (yes, Arm and Hammer) will do... about a teaspoon per day, mixed in system water...> I thought it was my test kit, so I went to my LFS and had them test it (they use a different, better product then what I was using) and they came up with the same low reading. My question might sound dumb but what takes the Alk from the system? <In your case, likely the other supplement component... and skimming, and algal growth... and more...> My pH is steady as well as my Ca. I think I need a shove in the right direction. :) Also I would like a lawnmower blenny. I hope he can help with the diatom problem. Or do you think it better to add more snails and crabs? <The Lawnmower Blennies mainly eat Greens (Chlorophyta)... Read through the Algae Control sections on WWM, consider a Ctenochaetus tang...> Or both? So sorry this is such a long letter! I thank you in advance for any help, big or small, you have to offer. <Study my friend. Bob Fenner>

Kole tang ich update and macroalgae Hi Bob Fenner, I wrote several weeks ago, several times, about my Kole tang with ich. Well, he has been in his hospital tank for two weeks, with a gradual reduction of spg to now 1.016 and temp at 82 degrees F. He is doing great ! As of yesterday, he had no more ich cysts present on his fins or body. He is healthy and his color is really bright ! I feed him brine shrimp in the morning, and a prepared frozen algae (mostly Spirulina) in the evening, then again at night. He actually comes to beg when he sees me come into the room. (Brine shrimp are his favorite food.) I suppose I will leave him at this spg for another 3 weeks since the main tank will have been fallow for 5 weeks at that time. Is this too long to leave him in this low salinity water? (Total of 3-4 weeks in spg=1.016) <No problem> About the main tank,... I have begun to stock the refugium part of my sump with macroalgae (have only actually purchased 2 different kinds, but as of last count have 6 different kinds present,....) Since I upgraded my lighting down there to 64W power compacts (15 gallon refugium area), things have begun to pop up everywhere. I have one kind of Halimeda which has very large "leaves" and is beginning to cover up a small piece of coral which has just began to extend its polyps for the first time. Both are located on a piece of live rock I purchased back in April, they have just never been under sufficient lighting. I would much rather the coral get to growing, over the Halimeda, but is there any way to pick the algae off the rock without harming it and "replant" it somewhere else in the tank? <Best to make a small "chip" off the rock with the holdfast mechanism of the Halimeda intact on it> Thanks for the constant, consistent advice, The recovering pet hospital, Jana <Thank you for the update on your continuing progress, success. 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 phenomenon.. 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>

Not So Mystery Marine Algae  Over the past two months I have noticed the growth of three transparent very dark green/blackish growths on my live rock. They seem about the size of a marble. I find it resembles a type of pod. What if anything could be growing inside? They is no movement but is very slowly growing in size. <Very likely some sort of "Valonia" algae. Please see the "Green Algae", "Algae Control" sections on the Marine Index part of our website: www.WetWebMedia.com for images and information on the control of these life forms. Bob Fenner> Thanks !!! Walt

Marine Algae/Feathery I.D. Robert I have a question about alga in one spot of my tank. I looked on the FFE site and wet web media of course, and haven't what I was looking for. My reef tank is great , I was wondering what kind of alga looks feathery. Un fortunately I am colorblind but I think it is green I think) It is growing next to the Caulerpa I have in my tank. This stuff looks like a bunch of little feathers. <Derbesia as a genus is very common in captive reef systems... and feathery in appearance> I have a purple tang and haven't seen him pick at it, but I feed him regularly so he probably isn't really looking for anything else. My tank is totally encrusted with coralline and looks great. Is this just a nuisance alga? Should I take out the little bit that is in there or leave it? <Nuisance... yes, as in not very palatable to common algae eaters...> ps I just finished your book for the second time and am adding it to my collection. thanks and take care <Ah, glad you're enjoying it. Do consider depriving these nuisance forms of nutrient... and growing desirable macro-algae that will produce chemicals to further limit its growth. Please read the "Algal Filtration" and FAQs sections on the www.WetWebMedia.com site for the particulars. Bob Fenner>

Green Balls? Valonia... Bob, I have written you in the past with some different questions and would like to say thank you again for your past advice. I have some new things that I would appreciate your advice on. A real quick low-down on my system is 125 gallon aquarium with a Sea Clone protein skimmer (I know that I could do better here), two Emperor filters, VHO lighting, 1 inch of live sand and roughly 70 pounds of live rock. I currently have two green dragon wrasses, a six line wrasse, a Foxface, and two orange diamond gobies. I have two toadstool leather corals, some green button polyps, and a couple of mushroom anemones. My aquarium was having some problems in the beginning and I suffered a few losses before realizing that the well water that I was using was using me to have high phosphates. I proceeded to purchase a RO Filter and have made quite a few big water changes, even more small water changes, and am continually topping off the water with the new water that I am making. My phosphate levels have dropped slightly but for some reason I cannot get rid of them completely.  <Good progress so far... the phosphates are "cycling" in your system... and re-cycling...> They are currently measuring at 2.0 ppm. <Yikes... I'd grow and toss some Caulerpa algae here... sort of like the use of biomass accumulators (e.g. Hyacinths and wastewater) to gather and remove nutrients from solutions> I don't over feed so I don't think that this is the problem. Before purchasing the RO Filter my leather corals would hardly open up. Since purchasing the RO Filter, my leather corals are almost always open and seem to be growing. I am happy for this but have had some bad luck with trying to add any new inhabitants. In the past few months I have tried adding a Naso tang, yellow tang, Kole tang, and lastly an Emperor angel all at different times and have watched each one get sick and die in a week or so.  <As an indicator, wait on any new livestock till the phosphates are below 1.0ppm, better 0.5ppm...> I think what that died from was ich or velvet. I have done all the environmental manipulation that you suggested but wasn't able to save any one of them. The loss of my emperor angel really bothered me because it was my favorite fish. It used to eat right out of my hand but for some reason I could not keep it from getting sick. I was able to treat in a hospital tank a couple of times but each time I put it back in the main tank it would eventually get sick again and eventually died. My original fish are still alive and don't show any signs of anything. For this reason I don't think that I have a parasite problem so much as that the water quality wasn't good enough to keep these more delicate species alive. <Hmm, no... more likely you have a "toxic tank problem"... that you are salvaging bit by bit...> One thing that I do have in my tank seems to be some uncontrollable green algae. For some reason I can't keep this under control and I think these little green balls that came with my live rock may be causing it. Originally there were only a few little green balls on some pieces of live rock but have recently noticed that they have spread to many other rocks. <Yes... likely Valonia... see the "Algae", "Green Algae", "Pest Algae Control" sections and associated FAQs pages archived on our site: www.WetWebMedia.com> They have almost encrusted this one rock. Finally, here are my questions. What are these little green balls and are they the cause of my green algae problem? Does the presence of the green algae contribute to the high phosphates and do you think this may be the reason why I haven't been able to keep some of the more delicate fish? Again, I want to thank you for any insight you may offer. Gianluca <Green algae group, Valoniaceae... not a direct contributor, but a recipient, user of nutrients... not toxic per se... read the many related sections on the WWM site. Bob Fenner>

C. taxifolia Bob, I have seen some references to potential algae problems in the local area, specifically Caulerpa taxifolia. I receive an e-mail the other night from a woman who wanted to ask me some questions about this algae, other algaes and the hobby. I spoke with her tonight and within the conversation she informed me that there is potential legislation to make ALL species of Caulerpa illegal in the State of California? <Have heard of this, yes... You are aware of the "Lagoon" fiasco here in town, with the gov't overreacting as usual, toxically nuking an area where this species had been proliferating... probably from a hobbyist release... And the many square miles in the Mediterranean...> are you aware of this, and its issues ? <Only vaguely... the typical knee jerk, half-cocked "let's protect our jobs" bureaucratic huzzah... like, um, the Garibaldi protection, the disallowal of small freshwater turtles... the rationale doesn't hold up... but it gets press, votes for "doing something"... and we get... more simple servants, taxes! What would you do?> since you are such a knowledgeable fellow....I suggested that she contact you, especially since this is an issue that is San Diego related Jim, Aquarium Design <Ahh, great. Bob Fenner>

Re: C. taxifolia Bob, I have heard of the Mediterranean incident, and originally I was under the impression that episode in San Diego was an isolated situation that was simply being monitored. <No... poisoned to prevent spread... millions of dollars... typical> additionally I have seen a few posters placed on the walls at the wholesalers. when asked if I could be interviewed I said yes, expecting to simple flex-my-wings. as the interview went on it became apparent that these people are out-of-control, and working with 'scientists' who " have a hard time specifically identifying C. taxifolia from C. mexicana" and as a result have decided to broadly list all Caulerpas as problematic. <Yes... also all too typical.> my greater concern is their attempt to legislate a law against Caulerpas in the state of California.....not so much against Caulerpas, but if they are successful then that starts a bad effect in the house-of-cards that we call our hobby. what's next ? <Reasons to search, seize, arrest, fine, incarcerate, tax, confiscate... Nazi-pettish control... The BIG "C", that's what government is all about here... Bob Fenner> Jim

Bryopsis Hi Bob, Recently, I've noticed a small (so far) outbreak of what I think may be Bryopsis. It is fine feathery looking stuff growing in clumps. Snails, hermits and Bicolor Blenny have shown no interest in it. Is there anything out there that eats the stuff but won't pose a threat to my corals? <Does sound like the genus... and there are a few possibilities... I would try a genus Ctenochaetus tang... maybe a Mithrax Crab... possibly a genus Salarias, Atrosalarias blenny... And consider,,, oh, I see you mention this below....> I've heard some types of calcareous macro algae will help inhibit it's growth. I have Halimeda discoidea and another similar variety, Caulerpa serrulata, Caulerpa racemosa and a type of red macro algae. <Yes, and am surprised that the other macro-algae you mention haven't been doing the same...> I have noticed, for the most part, the Bryopsis does not grow near these macro algae, but grows to within about 5-6" inches away. Will the good macros eventually out compete the Bryopsis?  <There is that hope, but I would also consider urging the encrusting reds by possibly increasing alkalinity... maybe culturing in a separate sump...> I keep the Caulerpas trimmed back to just a small area in a corner but let the Halimedas grow at will (the Bicolor Blenny keeps it trimmed). Should I let the Caulerpa patch get a little larger? <I would, yes> Here are the tank specs. 80 gal, 80 lbs + or - live rock, Skilter 400 skimmer (yeah, I know...just put in an order for a Aqua C Remora Pro HOB today), 4 X 96 watt PC lights, 2 powerheads for circulation, salinity 35 ppt, top off and change water is made with RO, PH 8.3, Alk 3.5, Cal 420, Ammonia and Nitrites 0, Nitrates <5, haven't tested for Phosphates. Livestock = Assorted soft corals, mushrooms, star polyps, button polyps, Lemnalia, colt coral, Xenia (pulsing), Sarcophyton, Sinularia and Lobophytum. Assorted hard corals, Hydnophora, Caulastrea, Tubipora, Turbinaria, Goniopora, Fungia, open brain and Euphyllia divisa. Fish, Pair Banggai Cardinal, Pair Amphiprion ocellaris, Bicolor Blenny and Common Firefish. Blue legged hermits, Astrea, Turbo and Nassarius Snails, 2 hitchhiker clams and 2 or 3 hitchhiker crabs, Cleaner shrimp and a couple Peppermint shrimp. Hope you don't mind the long list, but I figure the more info on tank the better. Thanks, Kathy <Sounds like a very nice system... I would take my time here... shoot for the gradual change... and let's see if the free-ranging Caulerpa doesn't curtail the Bryopsis... slowly. Bob Fenner>

Hair Algae Hi Bob, My tank's been running for four months now. I have hair algae growing in the gravel. It does not grow on the live rock. I have about 24 hermits and a blenny for grazers that seem to keep it off the rocks and maintain the "lawn" on the gravel. I'm always reading comments/questions on how people must rid their tanks of this horrible algae. I like the look of it. It "blows in the wind" and has a soothing effect when you watch it. My questions is, as long as it doesn't overtake my corals, is it wrong to leave it in the tank? Thanks again and hope all is well, Tony <No problem with having some of these algae... a sign of a healthy setup... just, as you say, that it doesn't get out of hand, cover too much, cause chemical, physical imbalances... you'll be able to see this develop if it happens. Bob Fenner>

Bryopsis algae Hi Mr. Fenner, I really enjoy reading your book "The Conscientious Marine Aquarist" it really gives me a wide ranging knowledge about marine aquaria. Currently I have a 150G reef tank. Everything is going fine except I have a major algae outbreak called "Bryopsis", do you have any idea how to get rid of it. I have try many thing such as using surgeon fish (I have a blue/regal tang and also a purple tang) they don't seem to touch the Bryopsis at all. I have also tried using phosphate remover, still no luck yet. Please help. Victor <Thanks for writing, and your kind words of encouragement. Much appreciated. You might get lucky (don't always work), with using either a Mithrax/Emerald Green Crab (just one specimen is all you need to try), and a member of the comb-tooth tang genus Ctenochaetus... I'd place both the fish and the crab... and you can read over the Tang species choices on our site: www.wetwebmedia.com  Be chatting, Bob Fenner>

Hair Algae Hi Bob. I have another question for you. I have an incredible explosion of what I call "hair algae" in my tank. It covers all of my rock and is a real problem. The stuff breaks off and plugs up the intake for my filters, covers everything so that's all you can see on the rock...you get the picture. I've added hermit and left-handed crabs, about 40 total (I have a 125 gal tank). I probably need to add more of those little critters but my question is this: What kind of fish, if any exist, would you recommend to add to help curb this problem?  <There are a few... look into short-circuiting the source of nutrients (and light) as control mechanisms as well... read on through the materials stored Home Page on set-up, algae control... and Salarias, Ctenochaetus, Zebrasoma...> I was thinking tangs and angels...yes?? <Maybe a Centropyge would help... but growing macroalgae in the tank or a sump with lighting would be better, more efficacious> If so, how many of each species should I look to add?  <One each... and different appearing...> I understand how the biological load on the tank works, I'll keep in mind the existing fish that I have. I don't have many right now, I'm changing to a more reef environment so my number is pretty low for my big tank. <Good... take your time... important> BTW....about a month ago I added three anemones, a Sebae, a bubble and a long tentacle. The bubble and long tentacle are doing great, the Sebae died within a week. Would you be inclined to think that there was a problem with that particular Sebae, in light of the other two doing fine, or are Sebae more difficult to keep alive?  <All anemones are tougher than folks realize... Sebae's are even easier to lose> I know there's a lot of unknown variables here, but any info would be appreciated. Thanks much, Betsy >> <Indeed... Bob Fenner>

Plant life Hi Bob, I just found FF and your column. Wow...it's a goldmine! I have a plant, growing on a piece of live rock. It has flat leaves that are kind of round and segmented. It is very dense and has some white "buildup" of some sorts on some of the leaves. It had some of this when I bought it last week and appears to be increasing. Any idea what it is? What kind of plant I have? I know I didn't give you much to go on, so any suggestions at all are welcomed! Barry >> Well, it sounds like some sort of encrusting or biomineralizing green... my best guess is a species of Halimeda... and they do get "crusty" under the some conditions (high calcium, alkalinity)... a good thing and good organism. Bob Fenner

Hair algae I am TOTALLY new to salt water tanks. I am still studying up and trying to learn all the terminology and noticed mention of hair algae which I have just noticed is in my tank. What causes it and how do I get rid of it? And is it dangerous to my tank life. I have crushed coral flooring and no live rock but I have 11 fish. I just purchased yesterday to scooter blennies and 2 crabs. Will they eat this growth on the flooring? >> Hmm, welcome to the marine part of the hobby! And do keep studying, investigating what it can/could be for you...  Filamentous algae are almost inevitable in marine systems... and some amount is desirable. They "just" start as spores from the air (even far away from the ocean), with other livestock introduction, decorations... even foods. Their control involves a many-stepped approach at limiting nutrients (proper foods, feeding, filtration, maintenance), competition (using macro-algae, other photosynthetic life to deprive noisome algae of light, food), predators (unfortunately not the animals you mention), and chemical controls (biological ones are the only to seriously consider... made by algae/mud filters)... Please take a look at the Algae Control materials stored at my website: www.wetwebmedia.com under the Marine Index for much more, details. Bob Fenner

Bryopsis Hi Bob, Well, my tank has finally recovered from its crash. Still no idea what happened! I have a question about Bryopsis. I have it growing in my sump/refugium, and it has also appeared on two rocks in the main tank. I understand it can spore and spread, and that it is very difficult to eradicate. I could turn off the lights in the sump, though I have a few leathers and polyps in there. But how to get it out of the main tank? Do you have any suggestions? I have heard talk about Bryopsis eating Nudibranchs, but am not sure how effective they are. Regards Jason Edward >> Hmm, are the filaments divided, like branches? I think this may be Derbesia... but nonetheless, the "cures" are about the same. Do look into out competing it by placing some Caulerpa in the main tank and lighted sump... It will soon be starved. Bob Fenner

Maintenance issues Thanks for your quick and informative response, I value and follow your advice because I've found that it works. One follow up question, if I may, how do you eradicate Halimeda from a reef tank when its growing from the live rock. A friend of mine has battled with it for months with little success. I'm battling hair algae on one of my tanks and seem to be losing that war as well despite using only RO water, feeding fish only three times a week, physically removing the hair algae from the rock, using Aquamarine's (reef safe) algae control product and doing 10% weekly water changes. >> Hmm, well, count yourself lucky if your Halimeda is doing that well... for me, I'd just occasionally clip off the bigger bits during routine cleaning. Regarding the hair algae, if the system is 55 or more gallons do consider getting a Lawnmower Blenny... a fabulous green filamentous scraper... only one, because this is about all they eat. And/or if it will go, look into a Mithrax (Emerald Green) Crab... also a great cleaner upper of filamentous (and other) algae. Do leave off with the use of chemical algicide... dangerous/toxic and unnecessary for your system. Bob Fenner

Hair algae (Derbesia) hi bob, thank you for answering my question concerning my hair algae problem. you mention in your response to get an algae blenny and some Mithrax crabs. Over the four months, I went through three algae blennies of the species you suggested. they died from starvation. they didn't touch the hair algae or any other food that was offered to them. as far as the Mithrax crabs are concerned, over the past year I put 15 of them in my tank. they did eat the hair algae. they were the only thing that really took a liking to it. I also noticed that they liked my stony corals as well. as I said, they did eat the algae, but didn't put a dent in it. over a months time they all died. you mentioned a fish that might eat this stuff. could you please give me the name of it so I can give it a try. this might be my only hope. as I mentioned before, I have a red sea Sailfin and a Sohal tang that only pick at the algae. not enough to make a difference. I stopped feeding them for a couple of weeks, figuring they would much out on the Derbesia but still didn't touch it. they got real skinny. thank you again for your suggestions. I look forward to hearing from you.  >> Hmm.... are you sure this is Derbesia? Not some type of blue-green (they come as filamentous forms too...). Three Sailfin Blennies and fifteen Mithrax?! If the two current Tangs aren't touching the algae much... I would not be too keen on trying some other members of the family... which would be my next best tries.  Instead, in case this is a BGA or even the green, Derbesia, I suggest trying two things at once: Overwhelming the filamentous with the use of Caulerpa (in the main tank, even if your tangs decimate it) and/or in a separate/attached sump (continuously lighted), AND raising and maintaining a high pH (8.4-8.5 or so) with daily administration of Kalkwasser... to precipitate out phosphates (among other things). Please do try this double-pronged attack... and make it known to me/us how this works out. Bob Fenner

Can't figure out the seaweed I have a 90 gal tank with live rock that forms a long type of algae seaweed that will not stop growing. I have tried to scrub it all off, yet it continues to grow back weeks after and it just gets longer and longer . it is like a thicker green hair algae and I don't know how to stop it. I was thinking about just starting over with new live rock because maybe this one has just had it. What suggestions do you have, Please Bob I am in need of  desperate help???? >> Well, I'll be desperate than... First, don't go the "throw out the old, get new" route... it won't work. Any small amount of spores from the existing filamentous algae will quickly (under the rest of conditions of your system) regrow the algae on the new rock... Instead, consider what the source of the nuisance algae growth is... and limit, or eliminate it. Do you have high nutrient levels? How much nitrate, phosphate? Do you have a decent skimmer? Clean it often? Do you have competitive life forms that will use up the nutrient, available light?  Next, do consider getting some purposeful filamentous algae eaters. If they'll go in your system without being eaten, get an Emerald Green Crab (genus Mithrax), and/or a Lawnmower Blenny... or/also a Combtooth Tang of the genus Ctenochaetus, or Sailfin (Zebrasoma) surgeonfish... Bob Fenner, your solution man!