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FAQs about Blue-Green Algae, aka Cyanobacteria

Related Articles: Blue Green Algae, Algae Control, 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: BGA Identification, Cyano Control, Cyano Control 2, Cyano Control 3Cyano Control 4, 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

Yes, BGA comes in nice red colors too!

Re: Additional carbon use. BGA toxicity    7/31/11
Dear Mr. Fenner,
5 weeks ago I had a problem with my fish becoming very stressed after I nipped a mushroom coral while siphoning Cyano out of my tank.
We were not sure if it was a result of a cascade effect from the coral or me returning the filtered siphon water back to the tank or both.
<Me neither. I would NOT return the siphoned water back>
Well, I can safely say it was not from the coral because I decided to move them to another tank the day after the last incident, five weeks ago, and today I decided to siphon out the Cyano and it has happened again.
It has again mostly effected both my clownfish,( scratching, rapid breathing, and darting around) and some of my other fish are also acting a bit stressed, however, not as badly as last time. Once again I replaced my Chemi-pure, and like last time, the fish are slowly getting back to normal. This episode has been going on for about 5 hours now and appears to be about 95% over. This time I did not return the "used Cyano water" back to the tank, all I did was brush some off a few of the rocks and siphon out the majority of the rest, just like 5 weeks ago.
During the last episode, my coral were also effected by my siphoning and brushing of the Cyano but, since I removed them I don't know if it's exactly the same issue. Does this sound like something that could be caused by siphoning Cyano or, do I possibly have some other problem in my tank or even some other form of Algae/Cyano?
<Highly likely is BGA toxicity at play here>
Everything had been going very well since I removed all the coral, the fish seemed very calm and happy. The coral were removed from the 38 gallon tank and have now been sitting in a 5.5 gallon, for five weeks, and they have never looked better! Needless to say, there is no Cyano/Algae/whatever in their tank. So while you were correct that the previous problems that were effecting my fish prior to these episodes were chemical warfare between the coral, I'm wondering if it was also the Cyano/Algae/whatever creating some sort of chemical "stew" in my tank?
Any thoughts? Sincerely, Art S.
<Please read here: http://wetwebmedia.com/bluegralgae.htm
Bob Fenner>

Saltwater version of 20 Questions... ;) Cyano Compatibility 12/18/08 Hi there! <Hiya> I've got a few questions for the experts. :) <OK> First of all, will Cyanobacteria harm a T. Derasa clam? <Should not but it is an indicator that something is amiss in your water quality.> Some sources that I have looked at actually say that these clams will eat any Cyanobacteria that they can filter from the water column. Is that right? <I'm aware of clams filtering nitrates out of the water and I guess Cyano spores could be present.> Also, I was wondering if a Fromia sea star would be compatible with a sand sifting sea star. <I don't see any problem here as long as the food supply is ample.> And finally, is it normal for sand sifting stars to eat Cyanobacteria? Mine seems to love it. <Not aware of that. Do read FAQ's here on your starfish. http://www.wetwebmedia.com/sndsftstrfaqs.htm> Then again, he seems to love everything I give him... which is fine with me! One less picky mouth to feed. :) I have a 55gal. long tank, Super Skimmer (for 65gal), Magnum 350 Canister Filter (for 85gal), 75lbs of live rock, and a 2inch deep sandbed. This has been set up for nine months. I bought four new T5VHO 54watt bulbs(2actinic, 2daylight) four months ago. Livestock includes one Pacific Cleaner Shrimp, one Red Scooter Dragonet, one Sand Sifting Sea Star, yellow polyps, Watermelon Zoanthids, 127 Pulsing Xenia polyps (my little sister decided to count them...she said she was bored.), some Caulerpa, cactus seaweed, too much Cyanobacteria, <Do read here and related articles/FAQ's on controlling Cyano. http://www.wetwebmedia.com/bluegralgae.htm> and a gazillion pods (no, the little sis did not volunteer to count the pods. Can't say I blame her. Lol.) Water parameters: Ammonia-0, Nitrite-0, Nitrate-0, Phosphates-.25, Calcium-400ppm, alkalinity-10dkh, pH-8.2. Thank you so much for your time and have a great holiday season! Cheers. <You're welcome and wish you the same. James (Salty Dog)>

Re: Red algae/System in general 11/13/08 Thank you again for the help. I just can't say that enough! <My pleasure.> I want to look at setting up a refugium. What are your recommendations for that? <Bigger the better in general. No need to spend big bucks on anything fancy. Any tank, plastic bin, just something that holds water will do.> Also, once I get the tank stable and have it that way for quite awhile, I would like to add new animals. What would you recommend (providing the current livestock makes it)? <Well, there is just so much to choose from, highly dependent on personal choice. Do look at/decide what you like and then research the individual compatibility with your livestock and system.> Would buying live plankton fish food help the mandarin and the starfish? <Dragonets can be sustained to a point this way, but it is far more cost effective to just set up a larger, mature system with a refugium and quite a good bit of live rock. Some have reported success with supplemental feeding the sand sifting stars. My experience tells me that these stars very often starve so slowly as to giving the appearance of success, for a time. A large sand bed is really needed for true long term survival. Scott V.>

Cyano a good thing? Greetings Bob & Crew! <James here today> This is sort of an unusual question but here goes.  Sorry for  the long explanation, but there is some background. I have a QT/holding tank that has housed a pair of Onyx Clowns (a  great find and hope to breed them soon).  I originally planned for them to  only be in the QT tank for about 6-8 weeks while their permanent home got set up  and cycled (found them and had to buy them before someone else did).   Well, I ran into some financial problems and their permanent home is set  up dry without live rock, sand or water.  I am back on my feet and  will be getting the live rock/sand next week. Now, they have been in their tank for about 6 months now.  It  is a simple 10-gallon with several pieces of PVC tube, a plastic Caulerpa and  (don't tell my girlfriend I said this) a really stupid looking fake  anemone.  For filtration I have a sponge filter and a HOT Whisper  30.  Doing 20% water changes every 7-10 days using water from my main reef  tank (already has a mated pair of Percs so moving them there is not an  option). As expected, the 10 gallon has a constant covering of brown Cyano and now green algae.  I have been diligently cleaning it off weekly.   My questions are this.  Can the Cyano and green algae be helping with the  filtration of the tank?  It is unsightly but doesn't it remove waste from  the water?  Would I be alright only cleaning off the front glass and  leaving the rest or should I continue cleaning everything? I moved a few small snails to the tank and they seem to be feasting  on the algae, but it is growing faster than they can eat. Thanks again for all your help!  I'll let you know when they  have laid their first batch of eggs and I have baby Onyx clowns! <Ray, Cyano is never good, very unsightly.  As far as algae helping with filtration, it won't detoxify ammonia, just help with nitrate control.  As long as circulation is good, you probably have enough bacteria in the tank to handle to waste from the clown.  I'd also use a good grade carbon in the Whisper to help remove dissolved organics.  As far as leaving the algae in the tank, I'd probably just keep the front glass clean.  A small protein skimmer will also help tremendously.  James (Salty Dog)> -Ray

Why is Cyanobacteria bad? I think that red looks nice. And Mandarin feeding Hello and thanks a lot for your help. I have 3 questions: <Okay> 1.-  I've read all your Cyanobacteria FAQs and I've read it's bad and that you must get rid of it, that it's a bacteria and not an algae, <Mmm, actually kind of both> and yet it does keep ammonia low and everything fine.  I'm a beginner and am trying to establish some Caulerpa and other "plant" in my tank, which means some of it dies and this red velvet appears (which I don't find offending), When I see the "leaf" fall and starts looking white, I take it away. I've read all the FAQs several times and don't get why is it bad? <These organisms are "bad" on two counts. Mainly their presence indicates unhealthful conditions for other types of life (invertebrates, fishes, algae...), but also BGA can/do produce toxic by-products that can mal-affect and limit the growth of other life. Folks don't need to panic and clean their tanks out completely, select a poison to try to limit, eliminate BGA if they see it, but should be aware as to possible root causes and seek to limit them... sort of like the mentality of turning a large ship with a small rudder> 2.-I started my tank 2 months ago, with collected saltwater and plants, live sand and live rock from my beach (yes I've read this is not the best) but I'm planning on keeping this simple and affordable.  I have lots of mini-critters (less than 1.5mm), 5 little shrimp (8mm) and about 15 Gammarus/copepods (2-5mm) (which I have seen at night pumps off and a hand lamp placed near the glass) <Neat> Thanks for your advice on this idea. Now, I got a green mandarin last week, my idea is to have a seahorse tank in the near future, and I wanted to begin with a fish with the same food demands but less picky. <Good idea> That's the only fish I have so far in my 40 gal tank, and it seems to be eating all day long, however I don't see anything on the rock when he sucks the water in (no I'm not blind, and I do use a magnifying glass), and I saw him spit back a worm once -one of the many times he sucked from the sand.  So my question is how big is the food for a mandarin? <Often very small... and nearly transparent... AND a great deal more and different types of food organisms come out during the night...>   He looks healthy enough but after reading all you FAQs wouldn't like to starve him at all.  Could I send you a picture just to be sure he's not thin? <Sure> I did see the picture from Lorenzo in your photo section but I don't see where is the "thin part" supposed to be, if you could add an arrow to the part to see it would be great! <It's the underside... "belly" area along the second half of the body. You'll see it be hollow, concave if it's thin.> 3.-As I stated before I'm beginning a biotope system, in the basics only (water, rocks, sand, phytoplankton and zooplankton) and plan to add the seahorses (don't tell me I need a bigger tank I've ordered my tank and will be a 100 gallon tall tank-this is just my experimentation tank-soon to be refugium) and maybe one more green mandarin, I've been feeding a little bit of brine shrimp too, but I'm afraid that it could take over the current critters I have and unbalance my system. <Mmm, no... Brine/Artemia don't really live that long, reproduce in the salinities of marine aquariums>   What do you think, should I quit brine shrimp and keep with what he's been eating or could both critters happily coexist? <I suggest a mix of the two> Thanks a lot and congratulation on your SUPER WEBSITE! Rogelio <Thank you for being part of it. Bob Fenner>

Dead Caulerpa/Cyanobacteria Questions (5/21/04) Hello Crew, <Steve Allen today.> I have a 50 gal reef tank where I have been battling reoccurring plagues of Cyanobacteria. As of 2-3 weeks ago, I put a couple handfuls of Caulerpa into the tank, which started to do well. <Ugh. I know there is disagreement among the crew about the value of Caulerpa compared to other macroalgae. Caulerpa has some real pros, but I think all would agree that it should be in a refugium, not in the main tank. IME, it grows like a cancer in the main tank, with the potential to choke of all other algae and even corals.> 3 weeks ago it started to disintegrate. <The downside of Caulerpa.> My protein skimmer was producing a lot of smelly waste, about 1/2 to 1 cup a day. I removed as much of the dead Caulerpa as I could find. <Good> Apparently, much of the waste accumulated in between the rocks and the sand bed. <Yes> Lo and behold, the Cyanobacteria made an appearance and has not left. <Thriving on the byproducts of the decay.> Trying to get a handle on my problem, I have read a lot of info and performed a 15 gall water change with RO/DI water. I have come up with a plan to get this tank back on track and want to know if my course of action makes sense. The tank has 3-4" of Southdown sand, 96Watts of CF 50/50 and 96Watts of Actinic 03 all 1 months old, about 600 gal/hr circulation into a sump which is the source for a 2 1/2 ft high venturi PS built by myself, and about 20lbs LR and 15lbs of dead rock. No purple coralline has been able to grow in this tank, I believe due to high phosphates and low Ca levels. No corals are in the tank because of the cyan. Salt - Instant Ocean S.G. = 1.025 Alkalinity = 10dKH Nitrates = 10ppm Nitrites = 0ppm Ca - 120 !!! <Are you sure your kit is correct?> Mg = 1320 P = <.01ppm (Seems low but probably due to the test only measuring for inorganic Phosphate, while the organic Phosphate is taken up by the Cyano right? 4 fish = 1 Royal Gramma, 1 Azure Damsel, 1 Male and 1 Female Anthias I performed a water change of 15 gallons, cleaning under all the rocks, scrubbing them, and removing any traces of Cyano. Another change of 12 gallons was made 3 days later after siphoning any remaining Cyano. My plan is to first use Kalkwasser and SeaChem buffer to elevate the pH, Alkalinity, and all too low Ca levels. <Read carefully how to do this. Another good option is B-Ionic 2-Part supplement.> Could this have caused the Caulerpa to die off and thus release the organic phosphate? <Hard to say, Caulerpa can be touchy. If it crashes or goes sexual, it can wipe out your tank.> Meanwhile I will be keeping an eye on the skimmate from the PS to ensure it is operating optimally. I am hoping this will provide the proper water quality to re-introduce the Caulerpa for nutrient export. <I strongly recommend against putting Caulerpa in the tank. It's too risk. Much easier to tend and prune in a refugium. You should consider a CPR AquaFuge if no space is available in your sump. Personally, having experience with both, I'd say you're better off with Chaetomorpha. Mine grows like gangbusters in my 25" AquaFuge with 65W PC lights.> When should I reintroduce Caulerpa into the tank, water parameter speaking? <Refugium> Secondly, once the Caulerpa becomes established, start to change the LR with newer pieces to repopulate the microfauna diversity. <The stuff will completely cover your rocks & sand with a carpet of Caulerpa. It is a prolific marine weed, ivy-of-the-sea so to speak. It is useful if carefully tended in a refugium, but it's a big messy pain in the main.> At this point I hope to be in the position to start adding corals like I once did prior to starting over from a previous Cyano plague (different skimmer and bioload). Any advice you could give me would be greatly appreciated. Glenn Koenig <Buy and read Anthony Calfo & Bob Fenner's "Reef Invertebrates." It has a fantastic 100-page section on macroalgae and refugiums.> 

Nuisance Algae ID Thanks for your response Bob! <Welcome> I'm attaching a couple more pictures from about a week later to show how bad it has become. Also because an LFS told me this was hair algae and not BGA. If these pictures make it any clearer can you confirm that you guys still think this is BGA? I'm double-checking because the treatments differ and I don't want to start one expecting results only to find I'm treating the wrong thing! <Mmm, time to refer you to WWM again... give the stuff a look under a scope... it will lack organized nuclei... organelles... and feel very slimy... it's almost assuredly Cyanobacteria/Blue-Green Algae> Also, if this is BGA and my nitrates and phosphates are 0 could it be that the Cyano is using all these negative food sources such that they don't appear on tests? <Ahh! Yes my friend> Since all my water tests out well the only food source I can think of is detritus on the sand bed/live rock. As such I'll work on suctioning excess and enhancing the clean up crew. Thanks again for your help! <Do read through WWM re BGA control... Bob Fenner>

Nuisance Algae ID Will do. Who would have ever thought a microscope was a requirement for my reef tank! Thanks again Bob! <"It's a whole other world in there"! Welcome, Bob Fenner>

Genicanthus, sumps and slime algae - 3/22/04 Hello, I have a few questions for you, I have a 60 gal reef tank about 2 years old (40 gal Q tank) 2- 55W fluorescent 2- 55W actinic, Magnum 350 with carbon and a BioWheel on the return, CPR BakPak, powerhead (528 gph) with rotating arms, I have 3 clams, 2 anemones LTA, a brain (debatable), an elephant ear sponge, a colony of buttons, frogspawn, and a hammer 100 lb LR, we also have 2 cleaner shrimp and a lawnmower blenny and crabs and snails. <Wow, you can keep corals with that little light??>  We have recently purchased a 4x65 (2 white 2 actinic) pc fixture and are awaiting delivery. <I would have personally went with all four bulbs at 10000K with no actinic but you config will be fine.> We would like to go to a sump but don't know where to begin, I am currently looking through your sump info. <The best place to begin. Develop questions then email them in> Our skimmer used to produce a good amount of waste but now has backed off a bit. <Need to clean the dickens out of it and be sure the cup is about 1/8 of an inch under the water line. Also as tanks age, they sometimes seem to go through changes as more waste is used by animal and processes.>  Our water readings are: Am 0, Ni 0, Na 20 ppm (big concern?) <Nah> Ph 8.2, Cal 440, Alk around 3 and KH around 10 (or vice versa, problem switching these two)  We feed BioPlankton about every other day, mysis and brine- occasionally to use it up. <Sounds like a good regime to me.> I also add Kent Marine Essential Elements approx every 2 weeks and directed on the bottle. Everyone is happy in the tank and growing. Unfortunately our ballast went out on the light & only two work and we are rotating between white and blue and the new one wont be here 'til Friday so we are hoping to get through that, if its not one thing it's another (second time in 3 months so new one was in order- Helios brand). <Cool. I hear ya though, reefkeeping can be a hassle sometimes> My question- finally- is this an acceptable system? <Sure. Why not? Two years is a new tank for sure. I would upgrade the light though. If you plan on any more light needing inverts like the clams> would a sump be a good idea? <If the fish load is high.>  also we seem to have recently developed a problem with black and red slime algae I don't want to go throwing stuff in to get rid of it unless there is no other recourse, <Check out our site for more info on this>  we did upgrade the powerhead from a PowerSweep 228 (approx 295 gph) to the stronger one (528 gph). <Good idea but be aware of dead areas in the tank. Powerheads have very laminate flow. Meaning a straight and narrow scope of water output> I read the following in regards to the slime algae and would like some more info "investigate and solve the root causes of this problem... Poor circulation, poor aeration, too much nutrient due to: Overfeeding, poor filtration, poor maintenance, lack of competing organisms for light, nutrients" <What's to say here? More water changes, less food, more water movement will most times solve the issue.> Also when feeding the BioPlankton should I turn off the skimmer for awhile?  <Yes.> I have been investigating angels and reef and found that many places recommend the family Genicanthus as "reef safe" due to be planktivorous, what are your thoughts on this? <Genicanthus angelfishes in general are "Reef Safe"... best to start small (3" maximum), keep in large (hundreds of gallons), fully-established reef systems with plenty of healthy live rock, flourishing refugium for foodstuffs> I really appreciate your time and help so that we can make our tank the best we can within our means. <Thanks for being part of it all ~Paul> Thank you Melissa Recla

What a Slimeball! >Hi >>Hello. >I did a 5 gallon water change on my 75 gallon tank and all was fine till the next day. I noticed a little slimy green dark algae. >>Ok. >This tank has been running for 8 months. Then today I noticed it's covered the entire bottom of the tank. >>The slimy algae?  That would likely be Cyanobacteria, a result of excess nutrients. >I have a protein skimmer, an Emperor BioWheel, 2 power heads. >>This does NOT appear to be sufficient filtration for such a tank, but I can offer very little as I have very little information to go on.  I can only hope the skimmer is working very well, and producing very thick, dark, nasty skimmate on a regular basis. >Can't figure why it grew because doing the water change usually reverse the cause of algae. >>Unless your make up water has nutrients present (nitrate, nitrite, phosphorous are the places to start looking). >My guess is there too much trace minerals being introduced from the new salt. >>I've never heard of Cyanobacteria or other true algal forms being caused by excess trace minerals (phosphorous being the exception off the top of my head). >How do I get rid of this unsightly algae? Thanks WWM crew >>You'd have to address your makeup water, testing before and after you mix the salt (with a QUALITY test kit).  Then address your filtration in regards to your stock load and feeding.  Those are the first, most obvious ways to start.  Marina

Red Growth on glass 2/12/03 Hi guys <cheers> Well after digging for hours through the FAQ, I can't find anything on this, so I'll ask: My 55g FOWLR tank has a strange substance appearing on it's back wall...it's a bright, pretty red "swath" almost like someone took a paintbrush and just slapped it on there - almost abstract even... From what I've seen of Cyano, it's NOT that - it's completely flat against the glass, it's texture would smear rather than "dust" off if you scraped it...  It's not taking over the tank or anything and only appeared after I introduced live rock. Any idea what it is and do I need to get rid of it? (It's not unsightly in the least, kinda cool actually) if it's some form of macroalgae, then hurray, that was why I invested in LR. Thanks, Xeo <a BGA perhaps, but hard to say without a picture and better description. Anthony>

Red Slime Bacteria Hi everyone- I am looking for a little advice from you folks again. Could you please read my following info and give me any advice you think may help. Sorry I am soooo long winded but I know you guys like all the facts. I have a 4 year old 55 gallon FO tank Hardware: -220w CF two 8000k and two actinic. The light schedule has been: actinics 4:30am- 10pm, daylights 5:30am-9pm. The lights are on so early so that I can feed the gang before I leave for work. I also feed again around 6pm. I give tangs (they are pretty big) about a 3 sq. inch sheet of dried seaweed twice a day and a pinch or two of Spirulina at each feeding for the rest. -Prizm skimmer -Emperor 400 filter on back -Magnum 350 canister with 1 cup bio-beads and filter sleeve livestock: -Tangs- 1 each- 6"-Naso, 5"-regal blue, 4"-yellow, 5"-Sailfin, <More than a bit crowded for this group. I would strongly urge you to look into a larger tank in the near future.> 2 original damsels, arrow crab and two sea urchins plus one of the 55 gallon "clean up crews" from FFE. They have all been in the tank for about four years and have now outgrown it. <Hopefully, they have not been stunted.> I am in the process of upgrading into a 125 gallon FOWLER, <Much better, but still a bit on the small size. Your current fish will be ok, but it does not leave much more room for additions.> but I want to make sure I understand and correct my current problem before I make the switch. <Ok> Water specs: -Ph- 8.0 -S.G.-1.023 -ammonia-0 -nitrites-0 -nitrates-10-20ppm -alkalinity-3.0 -KH-10 I change about 15 gallons a week with water that I run through a NEW under sink "double canister filter" one canister is for sediment and one canister is an activated carbon of some sort. <Ok...> I add Prime for chloramine. I mix water (Kent salt) and let sit (covered, dark, aerated, heated, powerhead) for about 24-48 hours. pH is 8. Nitrates are 0-10ish most of the time. <Ok> I have recently had a BIG outbreak of the red slime (Cyanobacteria?). I have had this a few times over the past 5 years and a little more diligence in the maintenance department always fixed it. The following is just additional info. I am just looking for any possible advice you may have. I have poured through your website info and I think I have done the things you suggest. Everyone seems healthy and are acting normal. But this time I have been battling "the slime" for a few months. Increased water changes, new CF bulbs (even though they were only 9 months old), added 20lbs live rock to "shake things up", cleaning up the powerheads (more flow), turning up the skimmer are not helping. <It maybe a seasonal problem. Tap water is generally much worse in the summer due to increased runoff from agriculture and lawns. Your under sink treatment does little to remove these nutrient sources.> It keeps coming back within a day of so. It seems like it dies off a bit over night but when I turn the lights on, it really takes off. It has been at least 3 weeks since any of these changes and it is not slowing down. One thing I did change before this started was that I took about half of the bio-beads out of the canister filter because I was starting to have consistently high nitrates (50-80 ppm). <Probably not related to your current problem.> I also replaced 1/3 of the crushed coral substrate with a few inches of fine crushed aragonite. The nitrates dropped way off but about a month later, "the slime" started. Did the decrease in bacteria cause this? <Could be related in that your decreased nitrates threw the nitrate/phosphate relationship out of whack and towards conditions that favored Cyanobacteria. Nitrate and phosphate are needed by all plants, and in this case a photosynthetic bacteria, but in certain proportions. Cyanobacteria use more phosphate in relation to nitrate than most algae.> I would have thought the bacteria would have recovered in the past few months if this was the culprit. One thing that seems different now is that the front glass will get covered with green algae within a few days. And there are tons of bubbles in the green algae and in the red slime. I don't remember seeing all the bubbles before. What would cause them? <It is a product of photosynthesis.> Also, it looks like the green algae is growing on the surface of the water. I have never had this happen in 5 years. I clean it off but it still looks like there is a little bit of a slime coating on the surface. <I would try re-aiming your powerheads or adding more to increase total circulation and surface agitation.> I have never had an outbreak that is so stubborn before and I am running out of ideas. Can you suggest any other course of action? <An RO or DI unit.> Thank you for your help AGAIN! Dennis <You are welcome. -Steven Pro>

Problems with BGA Hello everyone- I am having a major problem with what I am assuming is BGA (it's about the same color as coralline algae and looks like velvet). After reading over most everything on your website, I'm not sure of what to do next, since indecision, may or may not be my problem. One of the answers that comes up a lot seems to be poor water movement. <Along with sufficient nutrients for it to flourish.> However, one of the powerheads is shooting on to some of the rock covered with this stuff. As it flutters in the current, it looks like my dog with her head out the window as we drive down the freeway. Between the pump and 6 powerheads, I have about 3000 gallons of water movement in a 180 FOWLR. I have an AquaC 200 but I get very little skimmate out of it, perhaps a cup or so a week. I wipe the tower every time I empty the cup. <Have you ever gotten better production, or has it slowed? Perhaps your pump needs a good cleaning, with a run in a bucket with hot water and vinegar.> The tank is lightly stocked and lightly fed 1-2 times per day. In the display there is 150-200 lbs of LR as well as some in the sump which has a bunch of Caulerpa. Just prior to my last water change, which is 45 gallons every 2 weeks (RO/DI), <Hopefully, you are regularly changing your prefilters (about every 6 months) and the DI cartridge (when the color changes).> the water checked at: SG 1.023, Ph 8.18, PO4 0, CA 180, NO3 3-5, KH 10.9, Temp 84. The CA has been low for the last few weeks, even with the use of a CA reactor. <There is something drastically wrong here. Your calcium level is way too low. At this point, several large water changes are in order to get the levels back to their proper range. At that point, the calcium reactor can maintain them.> The only additive I use is a pH buffer because it used to be around 7.9-8.0. <Could still be high yet, 8.2-8.4 depending on time of day.> About the time I started using the buffer is also about when the problem started. <The low pH was a sign of coming problems and the buffer was just not the right solution.> Lighting is an Ice Cap 660 and 3-140w VHO (1 actinic and 2 AquaSun) bulbs which are about 6 months old and are on for 12 hours a day. It's my guess that the problem would be with the lights although, I thought the bulbs were good for a year or so. <No, more like 6-9 months for VHO lamps. Best if you replaced them in sequence, one per month for the next three months.> If it is the bulbs, will replacements cause the BGA to 'go away' or should I clean it off the rocks? <Physically remove as much as possible, too.> If I do clean the rocks, can I scrub it off while in the tank or will it floating around cause more of a problem? <Scrub it off, but then vacuum as much of it out as you can.> I've tried vacuuming, but the stuff doesn't come off the rocks very easily. <Perhaps you do not have BGA. There are some short maroon hair algaes, but their cause and treatment are still the same.> Around the same time as the outbreak, I've lost 4 cleaner shrimp that I had for about 1 1/2 years and most of the clean up crew. Everyone else in the tank acts happy and healthy. <You are making me suspect for RO is in need of some maintenance.> One last question for now. I had Aiptasia in my sump, which I think I got rid of but, is it harmful if it's just in the sump along with no other livestock? <No, not as long as you control them. They need food just like anything else. Large Aiptasia outbreaks many times are associated with overfeeding.> Thanks for a GREAT website! Andy <Glad to have been of assistance. -Steven Pro>

Help - Cyanobacteria (maybe), Calcium...and more Calcium Hi again, <greetings> I have been reading about Calcium supplementation on your web site and have a few questions. I currently can not afford a calcium reactor.  <a fantastic device... do look into building your own... quite simple and there are many good DYI sites on the Web. Start with the DYI link on www.ozreef.org> I am using Kent Marine "Pro-Buffer dKH" and "Liquid Calcium". The problem I have it that I can not get the calcium level over 300 and the pH stays pegged at 8.0-8.1. I would like to get the calcium higher and get the pH up to about 8.3. <before you go any further..take a glass of aquarium water, test the pH, then aerate it heavily overnight and test it again. If the pH rises, you have a problem with gas exchange that must be taken care of first> I know you are reluctant to recommend Kalkwasser. <Bob, may be... but I am not. I wouldn't take calcium chloride for free...if you use enough of it, chlorides build and you eventually have a problem maintaining alkalinity/pH...hmmmm, sound familiar? I love Kalkwasser when it is dosed properly (add enough to raise your pH by no more than .1> My questions is, what do you think about Craig Bingham's suggestion of adding white vinegar to the water before mixing in the Kalk? Please be specific since I have not seen you mention this idea on your Kalk FAQ. <Neither Bob nor I have personal experience with this new technique> If you don't like this idea, how then would you suggest I get the calcium and pH up in my reef tank? FYI, the tank has a 3" aragonite sand bed, and a sump with Caulerpa and 24x7 lights on (in sump only). <confirm your readings on other test kits first. Then dilute the obvious imbalance in the tank with some larger water changes with an enriched sea salt (I'm happy with reef crystals). Be patient with the weak pH and alkalinity for a few weeks and only use a two part supplement (AFTER the water changes through dilution have balanced Ca and carbonates, even if still low)to gradually raise the levels back to par. It will work. But the tank MUST be diluted first. And the readings are not going to return to normal the first night that you use the two- part (B-Ionic) supplement. It will a take some weeks. But it will be more natural and gradual. Have faith. Anthony> Thanks again, Jay Schudel

Green Slime Hello Mr. Fenner, My question for you is about a pale lime colored, almost thin Jell-O looking substance that has started to cover my live rock. I have had my tank for two years, all parameters are within normal limits and I skim. I have three powerheads blowing water everywhere so there are no dead spots. The only new change has been an upgrade in lighting to 4 110 watt VHO's (55 gallon) which are on 11 hours a day. I feed very little once a day to 3 fish. Any help would be appreciated before I rip this whole thing down. Thank you very much. Ken <Is this mass thin? Non-spongy? This is likely "mostly" a colony of blue-green algae... with other organisms in association. Please read here: http://www.wetwebmedia.com/bluegralgae.htm re strategies for control, limiting this mass. If it proves "unstoppable" a "re-setting" of the principal balances in your system may be expedient... with the removal, physical cleaning of the affected rock, addition of some new on top... Bob Fenner>

Cyanobacteria infestation. Robert, Hello I have a problem. My 55 gallon tank crashed over the period of 3 days. Well I've got that straightened out now, but since then Cyanobacteria has infested my tank. <Not atypical as you likely are aware... opportunistic organisms that have been with (actually pre-date) us by a long while> I had siphoned it all out, and it has come back. I would treat with Fresh Water Maracyn, because it will kill both green, and red-purple Cyanobacteria. But it isn't safe with inverts. <Tienes razon. You have reason> I have about 8 Mexican grazer snails, and 2 large sally light foot crabs in the tank. Along with my Yellow tank that survived the Ammonia spike. Do you know of anything that will get rid of the Cyanobacteria? Or do you think that the Maracyn would be safe with my snails, and crabs? Thanks for any help that you can offer me. ~~Tomy~~ <Much to relate, and in my/some few lucid moments wrote down and posted here: http://www.wetwebmedia.com/bluegralgae.htm Perhaps a good idea to go for a walk first... start reading here, go on to linked files. We are soon to feel we know each other well. Bob Fenner>

Red algae problem i seem to be having a red algae problem..it is overgrowing the purple coralline algae on my rocks...it looks festive for the holidays, but i don't want this algae to dominate my system...i bought the red slime remover by UltraLife but haven't added it yet until i get your input...any suggestions? <Have you touched the "red algae"? I suspect it is either another species/group of corallines or the same species you have adapting to your prevalent conditions... by changing color. I would NOT use anti-algae treatments here> ...I've attached a pix for your perusal to confirm that this is indeed red slime algae.... <Can't tell from this image... scrape some off... look under a microscope. Read here: http://www.wetwebmedia.com/bluegralgae.htm Bob Fenner> thanks, knef 

Re: red algae problem dear bob, i can wipe the algae off the rocks with my fingers. it is almost like a thin coat of deep red, sometimes coalescing into sheets. I've got them on my filters, powerheads, rocks, etc. does this help any? <Yes... this definitely sounds like BGA, Cyanobacteria... Please read through the sections on WWM re. Bob Fenner> thanks, knef

Algal troubles Hi, a few months ago, I noticed that there was a strange type of plant growing on the rocks of my fish tank. I didn't really think anything of it, but it's spread onto all the rocks, the glass, and most of the plants. It looks like small blackish-green tufts of hair, and its almost impossible to remove from the tank. Can you tell me what you think it might be and give me some ideas on how to get rid of it without harming my fish and plants? <Sounds like a clear case of blue-green algae, aka Cyanobacteria infestation... You don't mention whether this is a marine or freshwater system, but the approaches to control are the same. Please read over this section of our site: http://www.wetwebmedia.com/bluegralgae.htm following the links, FAQs files. Bob Fenner> Sarah

Fungus/Algae Hello Bob. You have been kind enough to help me with some questions in the past, and here is another. I have a strange algae? growing on top of my sand. It starts as a small patch and continues to expand. Before it becomes obnoxious or covers the entire sand, probably every couple of days, I pick it out. Its like grabbing off some dead skin. I have also included a couple of pictures of it. What is it? How do I get rid of it? What caused it? Any info would be helpful. Thanks! Mark <Sounds like BGA - here are two of Bob's several articles on the stuff: http://www.wetwebmedia.com/bluegralgae.htm http://www.wetwebmedia.com/algaeconMar.htm -Lorenzo>

What is this algae? I have this weird type of algae in my tank that is very thick, has tons of bubbles in it, has a VERY bad odor to it(when I remove it from the tank I can still smell it for days after) and it grows all over the tank(even on a 5 pound rock completely covered with lavender coralline algae), and none of my herbivores will even take a bite of it. Also my phosphates and nitrates are at zero. What is it and how do I get rid of it? Matt  <See these articles on Bob's site. http://www.wetwebmedia.com/cyanocontrolfaqs.htm http://www.wetwebmedia.com/algaeconMar.htm -regards, Lorenzo>

algae Mr. Fenner, I have a 55 gal. tank w/a 6" hippo tang. flame hawk, 2 clowns and a bunch of live rock. Recently red Cyanobacteria started to cover everything. At first I thought some strategic spots looked nice but now I can't keep up with the stuff. The tank is run by a wet dry w/a protein skimmer. Can you help with any suggestions to get rid of this stuff. thanks <Yes, can/will definitely help. This is such a problem that I have a section on "Blue Green Algae/Cyanobacteria" and associated FAQs pages archived/updated on our www.WetWebMedia.com site... Please read these over, and the links therein and get back to me if all your choices aren't clear. Bob Fenner>

need help with BGA/antibiotic research dear sir, i have read your researches in the internet, and i found that it is possible to get benefit from your experience, because im interested in (antibiotic production from blue green algae), i will be thankful if you send to me any information about this subject with my thanks A.T.al_fawwaz <al_fawwaz974@yahoo.com> 14/2/2001 <Thank you for contacting me, but am actually just a populist writer of hobbyist and natural history information. Will post your note with your email address with your permission on the website with the hope that others may be able to assist you.  Bob Fenner>

Another Cyano question... Dear Mr. Fenner, My 55 reef (w/o sump) has been set up for roughly 6 mo. and is undergoing what appears to be a Cyano outbreak: dark red hair like growth on rocks and substrate. It seems to be concentrated on top of macroalgae and on my yellow ball sponge (areas of high nutrient concentration, I assume.) <Sounds like it...> Several events (or a combination of them) could have precipitated this: 1.) The motor on my Remora skimmer recently failed, and, I believe, worked far below capacity prior to failure. It has since been replaced. <Good... with a larger TAAM/Rio product or even better another pump line> 2.) I harvested quite a bit of macroalgae (Sargassum) from my tank at once. <A weekly to monthly chore going forward...> 3.) The substrate (2.5" of aragonite) was disturbed by a dislodged powerhead. <These will all "do it"...> I have also seen a drop in alkalinity (to around 6-7 dKH) despite consistently high Ca levels (450 ppm.) I am not sure if this is related. <Yes, probably... either/or both cause/effect, or following> I have read the FAQ's and questions on Cyano here at WWM, and I have taken the following steps: 1.) I have reduced my photo period to 6 hrs., although this may be detrimental to my bubble, star polyps, and xenia and is perhaps limiting the growth of competing photosynthetic algae, what do you think? <Maybe just the Bubble Coral (Plerogyra) in the short run... > 2.) I am doing a several 20% water changes, five days or so apart. <Good idea... vacuuming out the BGA where you can...> 3.) I am blowing the algae off the rocks before siphoning out water and running a micron filter for an hour or so after a water change. <Okay> It doesn't seem to be subsiding, however. Is there anything else I can do?  <Yes, sure> Perhaps a couple of larger/newer powerheads (I am currently using 4 X 130gph PHs)? <More aeration, circulation would certainly help... using some chemical filtrant as well (activated carbon, especially high-retentive type would help remove soluble phosphate... this could be a problem... Remove the plastic media from your filtration, any fluidized bed mechanism... Do employ some green macrophytes (Caulerpa, Halimeda species... particularly in a sump area with its own lighting... for all the reasons given on WWM... More?> Thanks again for your help! Rob Duff <Glad to add my dos centavos. Bob Fenner>

Red Slime Algae....arghhhhhhhh! Hi bob, I have a really bad Cyanobacteria bloom that is threatening my beautiful Gorgonian forest and would like some advice on how to handle it. I have a calcium reactor and was really running it aggressively with an output pH of 6.2 to raise calcium levels.  <Hmm, too low... I would switch to a more soluble feeder stock and have the effluent at no lower than 6.8... better in the low sevens...> I suspected that "excess" CO2 could be responsible for the bloom so, a week ago, I emptied out the reactor, cleaned it and replaced the media with Korallith (thinking that maybe the old media that came unlabeled with the reactor could be leaching phosphate as well). I am now presently running the reactor at the suggested pH of 6.5 (for about a week now). <Oh, guess I should read these messages all the way through before keying away...> This has helped a little but the cyanos are still present. <Yes, takes a while to beat them back...> I have heard of 3 things that I can do: 1. Increase Skimmer efficiency 2. Use potassium permanganate w/skimming 3. Use antibiotics. <Yes on first, no on the other two... KMnO3? Too dangerous... many, many systems wiped out by using this strong oxidant... and antibiotics? Too likely to outright poison a system,,,, or end up recycling the nutrients, etc. back into Cyano...> I really am against using any chemicals, especially antibiotics since they can kill good bacteria and possibly make the bad bacteria even stronger by making them antibiotic resistant. I am going to upgrade my skimmer pump from an Iwaki MD70RLT (1500 gph) to an oversized Iwaki MD100RLT (2000 gph) to try and squeeze out a little more skimming efficiency. Also, I have been using Seachem PhosGuard in an external Ocean Clear Canister Filter to reduce phosphates. It's been about a week and the phosphates are still at .2 ppm ! I feed only 2 items per day: 1 Seaweed strip from a feeding clip and 1 cube of various kinds of frozen Ocean Nutrition food. Anemones are fed scallops, squid, clams, or shrimp once a week. I do not know where the phosphate is coming from, but suspect it is being liberated from the detritus by the excess CO2.  <Your tapwater? Just the food..., Melting of the substrate, live rock matrix... any/all and possibly other possibilities...> I just got a new batch of clean-up critters in hopes that they will eat some of the Cyanobacteria and/or the detritus on the substrate and rocks. <Not the BGA likely> My questions are: 1. Is there anything else I can do to get red of the red slime beast ? <Yes, please read over my take on the BGA on the site: www.wetwebmedia.com> 2. Where the heck is all of that phosphate coming from ? <See above> 3. Is potassium permanganate safe for reefs and do you recommend it ? <No, and no> 4. Is my protein skimmer too small (1400 gph maximum water flow) ? <See you give your tank spec.s and skimmer type below... The pump could be larger for this down-draft type skimmer... Does it remove material continuously? It shouldn't... i.e. it should cycle to no material removed at times... Otherwise it is inadequate/undersized for the application> My water quality parameters and system description are: pH = 1.025 nitrite = 0 nitrate = 0 ammonia = 0 phosphate = .2 (this is high and i am using the Seachem PhosGuard to get it down, although it doesn't seem to be helping) <The Blue Green Algae/Cyanobacteria are conspiring (by poisoning other photosynthates) to keep this material in solution... don't worry too much about it... get other organisms to supplant the BGA and the HP04 will drop like a proverbial bomb> calcium = 260 <This could/should be higher, as you know...> silicate = 0 alkalinity = 9 dKH temp = 78 degrees F Tank volume = 300 gallons Live Rock weight = 550 pounds Filtering: ETSS 1400 with Iwaki MD70 pump ( I am going to go to a MD100 to try to increase efficiency) Additives: 1. Reef Plus 2. Trace elements from K2R calcium reactor Source water: Maxima HI-S, 4-stage RO/DI filtered water Bioload: small for this tank; only 15 fish (mostly small clown size) Janitors: Cerith, Turbo, Nerite, Astrea, margarita snails and Mexican red-legged, scarlet, blue-legged hermit crabs, 5 brittle stars substrate: Top = GARF Grunge(.25 "), Mid = very fine oolitic sand (3"), Bottom = Aragonite sand (2") Lighting: 2 X 400 W 10,000K MH and 4 X 250 W 10,000K MH Salt: Tropic Marin Water Changes: Automatic, 1 gallon per day Water Top off: Automatic via float valve in sump Sump Volume: 50 Gallons Thanks in advance for your help Chuck Spyropulos <I would do a few things here to "re-center" your tank... Do increase your Redox potential if you can (by increasing flow, function in your skimmer, possibly adding ultraviolet sterilization or better an ozonizer (fit into the skimmer air intake)...) and cut back on the CO2... especially at night. (I would turn the reactor off probably at night for this period).... And do add more aeration/circulation... especially at/over the worst BGA areas..... And most importantly "wage biological warfare" with the BGA by adding macro-algae... best to a brightly lit sump area... continuously lit... with Caulerpa (best) or Halimeda algae... And do have patience. Don't stoop to the antibiotic route... not worthwhile. Read over the site and FAQs... and we'll be chatting. Bob Fenner>

Red Slime  Hi Bob,  I've been on the losing end of a battle with Cyanobacteria. I have been  able to control it, but eliminating it has been a problem. I left the  country for 8 days to find my wife was feeding twice a day instead of once,  when I returned, red slime was EVERYWHERE. ( I guess I could always get a  new wife. ...nah, too expensive:-) <I'll say!> I recently read that Red Slime is  extremely sensitive to erythromycin; administering 250mg per 25 gallons  should kill off virtually all of this pesky bacteria.  <Not all types are... and the "cure" may take the rest of your livestock with it... careful> I'm in the process of  going from fish only to mini reef and would really like to put this behind  me. Any comments? <Please read over the BGA/Cyano piece posted on the www.wetwebmedia.com site's Marine Index>  My bio load is fairly low: 1- 5" yellow tang, 1- 3" hippo, 1- 3" Coral  Beauty, 2- 1.5" Clowns, 3- 1" Green Chromis, 1- 1.5" Royal Gramma, and 1- 2"  fire goby in a 8 month old, 55 Gal tank with 75lbs of LR. AquaC Remora  skimmer, 4 powerheads, 220W power compact white/actinic and (unfortunately)  a Fluval Canister 304. I am using the sponge filters in the Fluval but  clean them every other day. I'm dosing Kalkwasser and Combisan as directed.  Just recently bought a Spectrapure RO/DI. Water changes have been 10%  bi-weekly for the last 2 months. One of my powerheads developed rust on the  impeller. The manufacturer is sending out a new one, but unsure how this  will/has affected my tank? I hope my picture is painted in a way that you  may find the culprit, 'cause I'm really at a loss.  Hope all is well with you,  Craig Douai <Things and life are fine. Do look into increased aeration, circulation, some chemical filtration, more light/macroalgae culture... and pls note/use new email addr. Bob Fenner>

blue green algae Hi Bob, Beside the snails and the surgeon fish what else can help to get rid of algae ( brown type )? Because of my clown trigger I cant possible introduce the above into the tank. Thanks and appreciate. David. >> <Hmm, not really... Best to do what you can to set the system up with the best filtration, circulation... live rock and macroalgae in the tank or a sump... use chemical filtrants about once a month to outcompete and chemically starve unwanted algae... and leave the rest to simple maintenance... No problem. Bob Fenner, who says read over the Set-Up, Maintenance, Algae Control, and Algae survey materials stored on our site: Home Page >

fish question for the famous fishman HELP!!! My aquarium is being eaten alive by Cyanobacteria!!! SOS!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! The situation is critical! I went to three pet stores and they all suggested a general antibiotic. Having read both of your most recent books and a constant reader of WetWebMedia, Fish Man Bob says, "No!" to all general antibiotics. What can I do? Tank specs: 38 gallons Eclipse filtering system with in tank skimmer 10 lbs of tufa and 8 lbs. of live rock PH test 8.2, nitrate 8.0, no ammonia, no nitrite lighting: Power Glo 40 watts, 18000 Kelvin 80 Lux (sorry, they don't make vita-lites anymore). specific gravity: usually around 20 30 lbs. of sand Fish and invertebrate tank (fish + one Condylactis, two shrimp, turbo snail, and starfish). Tank is 1 1/2 years old and so far I've never lost a single fish for any reason!! <Yeeikes! Sorry for the late response... have been on a liveaboard in the Red Sea...> One other quick question: Condy has been at the top of the tank around the waters edge for about 2 1/2 months. Typically, after a water change he will swell to full size and then retreat a day or two later while always remaining at the top of the tank. Some time ago, he was very beautiful with filled tentacles cemented to a piece of live rock on the bottom of the tank. What gives with our friend Condy? What can I do to get him to come down? <All related... need to do what you can to eliminate BGA/Cyanobacteria causes/allowances... concomitantly this will improve Condylactis health> Before I leave you to ponder this question, allow me the opportunity to congratulate you on the fine work you do publishing on the web and in the bookstore. Your erudition saves the lives of thousands of fish and makes each of us constant readers more conscientious. Your photography is magnificent!! I personally always recommend your books. Having never had an aquarium before the salt water tank, I can say without a doubt that the Conscientious Aquarist is responsible for my success!! I simply turned the information into action!! Not only have a I tried to follow the golden rules of fish husbandry but I never miss an opportunity to take a pet store manager to task for selling sharks and my personal favorite, the Hawaiian cleaner wrasse. Yes. . .I do see that one in the stores occasionally as well as the false cleaner. <Wotta stroke! Thanks for the plugs... and your contributions> I've taken enough of your time. Help me get rid of this God-awful Cyanobacteria  (I am blessed with the red and green varieties), before the wife makes me throw the tank out!! Take Care. David Dowless living large in the City of Lost Wages <Hotay, now... let's look into increasing, improving your lighting... Yes, more intensity, time on... have you changed your lamps recently? They may well have lost strength and photo-shifted to non-useful wavelengths.... And do you use activated carbon? Do so, about once a month.. in a bag in your filter flow path... And how about growing some macro-algae in a constantly lighted sump? These are the first of many suggested steps to improvement... Let's get this dialogue going! Bob Fenner>

I have a 55 and 29 gal reef tank. Both are running off the same system. The only exception is the 29gal. which is the bottom tank does not have a surface overflow or as many snails as the top 55gal. tank. The top tank looks perfect, but the bottom tank has a lot of slime algae and Valonia. The same system, one looks good, one doesn't. What's the problem? One thing I didn't mention is that the top has metal halides and  the bottom has NO's run by an Icecap. > Thank you, Thai <Bingo! It's the lighting. At least upgrade the lower tank's system lighting to Very High Output fluorescents... Your ballasting should support these... and your slime algae (blue greens actually, or Cyanobacteria) will be a bad memory. Bob Fenner

Too much red algae I have a 6 mo. old 155 gln. saltwater tank (fish only) that is absolutely covered with red algae. It blankets everything and my tank looks like Mars. I am not positive it is red algae. I have heard it might be blue-green algae. I am wondering if increasing the light with 10,000K lights will help as I understand that red ( and blue-green) algae flourish at low-light levels. I already have a couple 6500K light bulbs, but the tank is still a little dark. >> Hmm, we're talking soft, lavender colored stuff? Yes, this is a type of blue-green algae, aka Cyanobacteria... and yes, they do proliferate in low light conditions (versus bright)... You only have "a couple" of lamps on your system (a 155?). It is under lit... and the 10k additions will help... as would increasing circulation, aeration, growing some other forms of (macro) algae, live rock... do consider a more comprehensive control program. You'll be glad you did. Bob Fenner

Re: Too much red algae Thanks for the info. I have searching everywhere for information on this problem. After I sent my inquiry I found your column and see that you get a lot of questions about algae! <Ah yes, no doubt, number one on the hit parade>  I have two 3' lights and one 4' light on my tank (it is a 6' long bow-front). I have one 6500K lamp in each of the 3' lights and regular aquarium lamps everywhere else. Still could use more light though. I'll try the 10,000K and see if it brightens it up. I can also add another row of 3 footers if I need it brighter. <Do add the lighting> What about filtration? I have 4 power heads and use under-gravel filtration. Would a better filtration system like a wet-dry system with protein skimmer help this problem? I am thinking about going that direction eventually anyway. <Definitely... do add these two elements... as soon as possible... a TurboFlotor 1000 (in-sump skimmer) will amaze you at the gunk it removes> My circulation is very good. My aeration could be improved. My maintenance is religious. Within 2 weeks of rinsing off all coral and sucking up almost all the algae from the gravel, it comes back with a vengeance. Now, live rocks. I would love to get some live rock, but I have coppered this tank in the past. Since then I have been running canister filtration with charcoal and poly filters. Coppers gone, but my understanding is that I can never go live rock since I have coppered. Is that true? <Don't worry... what little copper residual that may be there will be quickly and safely complexed by the live rock... or you can use a pound or two of activated carbon (a good idea once a month or so anyway) and it will be gone ahead of time> Also, can you explain what you mean by "do consider a more comprehensive control program"? I want to solve this problem and want to make sure I fully understand your advice. Thanks again for your help. <You, we're doing it right here: Talking, planning your improved, increased filtration and protein skimmer, addition of live rock, enhanced lighting... these are steps in a comprehensive algae (and water chemistry) control program> For a more unique, interesting problem... I did wipe out my entire tank (except one wrasse) by feeding an oyster to my trigger. That's another story. >> Yikes and not a pretty looking or smelling one... thanks for sharing (minimally!) Bob Fenner

help Hi Bob, I have a 55 gal with 2 power heads a protein skimmer a magnum 350 canister a overflow with bio balls 6 48in lights 3 actinic and 3 blue. I have a yellow tang and 3 damsels. I have had my tank set up about 4 months. I just recently lost a carpet and a long tentacle and I have a bunch of burgundy algae. It just wont stop!!!! It is all over everything. I just ordered 45lbs of Fiji live rock which is cycling as we speak. My problem is the algae it is so bad that no sooner do i wipe it off it comes back within hours. Can you please help!!!!! >> You're already doing what will make the biggest difference, adding the live rock... When you place it (or now), do place a unit/pad of PolyFilter in your canister filter... this will help to remove nutrient and pollutants from the soon-outcompeted blue green algae/Cyanobacteria (which is what this burgundy gunk is)... No other chemicals need apply. Bob Fenner

Algae? I have a 125g (Live Rock / Fish only) tank. I have 4X96W PC's w/ 3 yellow tangs, 2 blue damsels, 2 peppermint shrimp, 1 green brittle star and 1 (scary looking - black) brittle star. All of my water tests are in the norms but my alkalinity is a little low at 1.7 (PH is OK). I'm using Kent Superbuffer dKH to slowly raise the Alk. My problem is this: I have a reddish/nutmeg growth (algae?) growing on my sand and on a few pieces of LR. Also, my water seems slightly cloudy compared to it's normal appearance.  <Yes an algae no doubt... and likely a Blue Green/Cyanobacteria... though it's obviously not that color... and likely due to... oh, more below> I have a large W/D filter & a skimmer. Could the cloudiness be from alga blooms? And if so, I have Kent Pro Clear which touts it clears water - would this help and is it safe? Should I be worried and proactive regarding that nutmeg color growth? You have always been a BIG help - THANKS! <Yes, the cloudiness is likely from biological causes... probably linked to the low alkalinity... and about to be cleared by increasing the same... If it were my system, I'd add a teaspoon of sodium bicarbonate (ordinary, new baking soda) per ten gallons per day till the alkalinity was in the 3.5 range... otherwise, hold off on other "additives"... and "this too shall clear" Bob Fenner

Black Algae I have tried all other avenues of info, but alas, I have to bug you again! The left side of my 55 gallon tank has a film of black slime algae all over it. I have done 2 10% water changes within the last week, I have siphoned the substrate and all of my levels are good-pH is 8.3, alkalinity good, 0 Nitrates. (those are the only tests I have)-Everyone is recommending chemical additives to cure it, but I would really like to not do that. The algae is gone for about 3 minutes (ha ha) before it multiples. I use a wet-dry system, a CPR Bak-Pak and have 2 powerheads and about 30 lbs of live rock. The interesting thing to me, it is only on one half of my tank-but it is slowly spreading!! Plus, I do use RO water, only have 3 fish and feed sparingly-what is going on?? Thanks in advance Carolyn P.s. I did look in your book first, and it (yikes!) reads that if you have the undesirable black algae a serious problem with filtration, water movement is occurring (or something to that effect!!) >> Yes to the above reference... we must need look at developing conditions, circumstances that favor "other" forms ("higher") than Blue Green Algae (BGA), which is the Cyanobacteria you have here.... Do look into adding, directing powerheads towards this area... adding an airstone (like along the edge of your aquarium's inside... look into possibly elevating the pH to 8.4 or so with Kalkwasser for the express purpose of binding up a necessary nutrient: phosphate.... consider pulling the plastic media out of your wet-dry... a primary source of nitrate food for the BGA... Look into better, brighter lighting... the BGAs can't compete against true algae like the greens that would be favored by enhanced lighting... Bob Fenner

Re: algae and lighting thanks for a reply so quick. anyway the 55 gallon does not get this algae. only the 120 i have two sand sifting stars, many snails(Cerith, Nerite, Astrea, limpets, and the small pea like snails) left handed hermits and a sleeper goby. the problem was there when i first set up the tank and now is back . it has me stumped water parameters are great like i said and the upstairs tank is fine the only difference is watts per gallon that i can see being about 5.5 watts per gallon in the 55 gallon and the offensive 120 about 9 watts a gallon. this should not be a problem as i have seen many people use 400 watt metal halides anyway if you come across any answers solutions hints let me know and if i find the problem i will let you know so if you get this problem you can give suggestions chuck  >> A peculiarity of the/a "founder effect"... this species has become situated... and is excluding others... asi es la vida... cie la vie... this is the way it is... Bob Fenner

Starting Over Bob, I began a 46 gallon saltwater reef-type aquarium a year ago. I had a Skilter 250 filter and an AquaClear 402 powerhead with an under-gravel plate. The aquarium had two Clowns and a Regal Tang, snails and hermit crabs. I also had mushrooms in the aquarium. I had crushed coral substrate with live rock. The Regal Tang ate the macroalgae that had grown and green, brown, and red algae covered the rocks. The red algae smothered all of the mushrooms and some star polyps...the green algae did the same thing. I treated the tank with Myacin which killed the Red Slime algae..along with the invertebrates. I now have live rock covered 75% with green and red algae, my 2 Clowns, Regal Tang, and a few blue-legged hermit crabs. I replaced the Skilter 250 with a Berlin skimmer and the 402 powerhead with a 802. This should help. I plan on adding a "cleaner package". I think the Myacin killed some of the beneficial bacteria. Should I add Bacter Vital? Also, what can I do about the left over green and red algae? will AntiRed do the trick...or should I just rely on the new skimmer, powerhead and cleaner package. (Just added the new skimmer and powerhead yesterday.) Thanks!, Tammy >> Wowzah, quite an adventure... and thanks for relating it so well... I would "just" wait with the new skimmer, no more Maracyn (tm) (erythromycin), or the sugar/vital solution at this point... Perhaps your next investment should be a phosphate test kit... let's get the source(s) of the blue green algae (this is what the "red" stuff was) under control... with time, the skimmer, and maybe in a month or so introduce some macro-algae as a light and nutrient competitor. Bob Fenner

Hello! I was having a problem with blue-green algae and among other measures I have been using a phosphate absorber in my sump. I was changing it about every 4 - 5 days as recommended, but now it seems to have leveled out at .50 on the water test. Is that an "ok" level? Should I wait to change the beads until it begins to increase again? We are making some headway with the blue green algae problem. But we still go in weekly to "scrape" and do a water change...because the vicious cycle is so hard to break. As soon as some of it dies off it creates "food" for more to grow....so to speak...I can't wait until we can be rid of it! I am hoping to get some Halimeda in there soon to help...I am just still leery about when the right time to put it in without killing it is... ??? :( Thanks for your time! I look forward to your response. :) RT >> 0.5 ppm of phosphate is still too much... I would go ahead with the Halimeda... and increase aeration/circulation to the area most ill-affected... And if you are a Kalkwasser-user, consider dosing your system to the point of elevating your system's pH to about 8.4-8.5... You do have live rock? Adding some Caulerpa algae to your system and/or sump with a light would speed up the battle of absorbing phosphate and other nutrients, denying them to your BGA as well... Bob Fenner 

Should I use pH buffer to raise it to 8.4? I don't do the Kalkwasser drip thing. I do have live rock about 45 lbs. in a 92 gal tank. Rocks are still usually covered by the end of the week with hairy Bluegreen and now a new bright blue/ green version that isn't hairy but sure doesn't look "proper". :( We've been scraping with a toothbrush each weekend, but to get all of the dead stuff out it would probably take at least a 50 gal water change and we have been doing alternating increments of 10 and 15 gal. (each weekend)...so we are taking it little by little. Sigh. Thanks for your speedy reply! :) RT >> Hmm, if it were me, I would elevate the pH in this fashion with Kalkwasser for a couple of weeks... It does the trick.... Along with starting to introduce erstwhile filamentous biological controls... Like Lawnmower Blennies, Mithrax (Emerald Green) Crabs, "clean up" crews... Bob Fenner > Hello! I was having a problem with blue-green algae and among other >measures I have been using a phosphate absorber in my sump. I was changing >it about every 4 - 5 days as recommended, but now it seems to have leveled >out at .50 on the water test. Is that an "ok" level? Should I wait to >change the beads until it begins to increase again? We are making some >headway with the blue green algae problem. But we still go in weekly to >"scrape" and do a water change...because the vicious cycle is so hard to >break. As soon as some of it dies off it creates "food" for more to >grow....so to speak...I can't wait until we can be rid of it! I am hoping to get some Halimeda in there soon to help...I am just still leery about when >the right time to put it in without killing it is... ??? :( Thanks for your time! I look forward to your response. :) RT > >> >0.5 ppm of phosphate is still too much... I would go ahead with the Halimeda... and increase aeration/circulation to the area most ill-affected... And if you are a Kalkwasser-user, consider dosing your system to the point of elevating your system's pH to about 8.4-8.5... > You do have live rock? Adding some Caulerpa algae to your system and/or sump with a light would speed up the battle of absorbing phosphate and other nutrients, denying them to your BGA as well... >Bob Fenner

I have a 20 gallon high tank, which I am hoping to turn into a mini-reef system. I set it up about 3 months ago, and at that point it was gong to be a fish only tank. After about two months, I started to get a lot of algae. At first I thought it was rust on the coral, but it began to grow on the glass too. It's that nasty brown-red algae. What should I do to clear that up? Will snails or crabs be enough (I have four now), or is there a chemical I can add to the tank to kill it off. It's very unsightly, but I don't want to start over at this point. >> This rusty/red stuff is probably a/some type(s) of blue-green algae (not all that color), that is best dealt with by providing some competing macro-algae to compete for light and nutrients (add some live rock, and maybe some Caulerpa, Halimeda, or other macro-algae), and increased aeration/circulation... Direct a powerhead to better move water around your tank, and/or add an airstone. Don't resort to chemical controls here... the material that makes these algae up is toxic if released in the water by dissolving them... And unfortunately, few cleaner-uppers will touch this group of "algae" (they're more closely related to bacteria). Bob Fenner

Red Slime Algae I recently purchased a used 65 gal system with a live sand and 45-50lbs. of live rock. The inhabitants are a blue tang, yellow tang, two blue damsels, fire shrimp and a purple lobster. The tank was running for approximately two years for the previous owner and was in dismal shape. The water was practically yellow and the live rock was covered an mats of blackish red algae. I could see spots of coralline algae growth here and there. Therefore, being the eternal optimist (not to mention the cheap price for the system) I decided I could convert this mess into a thriving reef tank. Many water changes over the past months and the use of carbon has cleared the water. I slowly removed the bioballs out of the sump and am currently using a phosphate and nitrate remover. I also replaced the bulbs in the lighting system (2-15w NO daylights & 2-15w Actinic 03). I am planning on upgrading my lighting system to the retro 4-55w PC offered by FFExpress this month. The only new inhabitants to the tank are 40 knobby hermit crabs. While the tank is well on the way to recovery (small patches of coralline appearing), the red algae still exists in large enough amounts to still cause me concern. My question is how do I get rid of the remaining red algae. There are allot of products that claim to eliminate the red/slime algae problem without harming the fish and inverts. Can you suggest any ideas? All the original tank inhabitants continue to thrive and I don't want to add anything (corals, fish etc..) until the algae problem is in check and my new lights are installed. Any help you could offer in eliminating this red menace would be greatly appreciated. Thank you, David Eller  >> Thank you for writing... I'm an eternal (or is that infernal?) optimist as well... And I say, don't buy any chemical products to "take care of this problem"... Instead, when you get the new lighting, place some macro-algae... the genera Caulerpa and Halimeda are the ones most frequently employed... but there are many others available/useful (an article on who's who is archived at www.wetwebmedia.com), that you could/should use... The combination of mighty green algae outcompeting those Cyanobacteria (aka blue green algae... I know, they don't look that color) and your new lighting (only half on for the first month okay? To avoid photo-shock...) will be unbeatable! Bob "shining in the dark" Fenner

RED ALGAE I get a out break of red algae once every other month. When I treat it with chemicals it is quickly removed however the chemical seems to be harmful to star fish, slugs, etc.. Is there any natural way to get rid of this Red  Algae? >> Yes indeed... and thank you for pointing out the fruitlessness of using chemical algae treatments... They don't remove the root causes of the problem, the algae dissolve for the most part, but their "building blocks" and nutrients don't.... and their quickly back... poisoning your livestock all along the way with the treatment. Look to the root causes of these (actually) Blue Green Algae (BGA). Low light, low circulation, too much nutrient, lack of competition... Increase circulation, aeration. Increase the intensity and duration of your lighting (to favor other photosynthetic life). Remove nutrient by cleaning up, upgrading your skimming, periodic use of chemical filtrants, gravel vacuuming when doing regular water changes... Install an algae or algae and mud filter, add some macro-algae to your system... Bob Fenner

Cloudy Water I have an 80 gallon fish only tank. I had an outbreak of red slime and green algae. I tried to clean off some of my decorative corals and rocks and my crushed coral base. A few days went by and all of a sudden my water got very cloudy. I have checked my PH, Nitrate, Ammonia and Nitrite levels all are OK. I can't figure out what went wrong. All my fish seem to be fine. I was wondering if I should cut down on the length of time the lights are on the tank. They are on close to 14 hours a day. I have tried a water change but no change. What can I do. Gerard >> Hmm, well, you experienced an adverse reaction on the part of the "status quo" of microbes in/on your substrate with the efforts at removing the Blue Greens... I wouldn't cut down on your lighting... but would add some live rock (yes, even for a non-reef tank) and some sort of macro-algae (maybe just Caulerpa or a species of Halimeda)... and wait out the cloudiness otherwise... unless your measures of nutrient accumulation/cycling (like ammonia, nitrite) rise quickly... in which case, I would execute a very large (50%) water change... quick. Bob Fenner, who says, take the long, steady approach to managing your water quality

red alga? Hello Bob, I have a 30 gal tank and I recently changed my lighting to 2 x 36w power compact, and I added a rio 800 powerhead to my tank. I recently noticed reddish alga covering most of my live rock and even parts of the substrate crushed coral. What is this alga, will it go away and if not, how can I get rid of it or get it under control? I have an eclipse 2 with carbon filter and bio wheel. Could any of these be the cause? My water parameters look good although I have not tested for phosphates or silicates. How can I get rid of this red alga? thanks, Ben >> Thank you for writing... It may be that what you have, and soon will be gone, is a type of Blue Green Algae (BGA)... It should be displaced by other photosynthates (at least "micro-algae" greens if you don't stock other macro- and/or other light-using organisms). Do you utilize a skimmer? This would help to remove a great deal of "algae food chemicals"... and can be retrofitted on an Eclipse system. Do you use chemical filtrants? It might be prudent to slip a Polyfilter in your Eclipse tray at this point to "suck up" a good deal of the nitrates, phosphates to limit their availability to the BGA... Bob Fenner

Hello again! We have been working diligently to clean up a terrible Cyanobacteria problem (blue/green algae). We have all sorts of forms...bright green carpets, brown slimy hair, etc...I took the advice of an article on the Internet and we have been doing weekly water changes of 10% and 15% (alternating) with the use of a skinny tube siphon (of our own creation to minimize the water amount and increase the gross dying algae amount) and an interesting "toothbrush in a tube" we made for scraping the rocks. We bought Phoszorb and silicate remover and have been replacing them every 5 days...although now we are planning to leave it alone because the levels are much lower...around .5... and we'll probably replace it every 2 weeks until we level out. We are finally seeing results here...our clean up crew is finding the job a bit more manageable too. What I am wondering is...how long do you think I ought to wait to try growing more Halimeda in there? I have read in some of your recommendations that higher algae forms will help to control the lower form proliferation...we lost four Halimeda plants to the infestation...I really don't want that to happen again. We still have some blue/green algae in there...it will probably take forever to be completely rid of it...because it keeps regrowing...and a lot of the dead stuff is still in there. (It is hard to remove it without taking too much water.) What would you recommend? We have a Foxface so Caulerpa is out of the question unfortunately. Do you think it is too soon? We look forward to your response. Thanks! :) Ruth >> Hmm, good question... On the one hand, we agree that sooner is better... to compete for light, nutrients, and hopefully for the Halimeda to produce some chemical deterrents to thwart the BGA... on the other hand, the BGA can/will poison the Halimeda if it is present in large enough concentration... I would shy on the conservative side here... maybe try a Polyfilter in your filter flow path to give the BGA the coup de grace and in a month or so from now... with very little BGA present, stock a real healthy stand of the macro-algae. Bob Fenner


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