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FAQs about Green Macro-Algae Health/Disease

Related Articles: Embracing Biodiversity, Green Algae By Mark E. Evans, Green AlgaeGreen Algae 2Avoiding 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 1Green Macro-Algae 2Green Macro-Algae 3, Green Macro-Algae 4, Chlorophyte Identification, Chlorophyte Behavior, Chlorophyte Compatibility/Control, Chlorophyte Selection, Chlorophyte Systems, Chlorophyte Nutrition, 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

A lovely bunch of Ulva.

Early Autumn for Halimeda?       8/15/18
Hi Crew!
<Hey Dani>
I have been very happy with a Halimeda macro algae I got over a month ago. Yet I have noticed over the last week it is turning a “golden” color on some of the “leaves”. These leaves also seem to be affected by specs of coralline algae and look a bit furry as well.
<I see this in your excellent pic>
I take it that there isn’t really an Autumn season for Halimeda in the ocean lol—what’s it doing?
<Mmm; appears to be "suffering" from a lack in water quality and/or being outcompeted given present conditions. What re your Ca, Mg in particular? Water temp.?>
I have this feeling this older part of the Halimeda is possibly not doing well. I’m by far a reef expert like you all, but I do know some plants try to produce offspring quickly when they aren’t doing so well.
<Agreed; and likely relevant... the month of your having this algae... takes a while for it to adjust or show signs of not doing so>
In the last week I’ve seen multiple sprouts coming out of the rock frag this Halimeda is on. Should I clip off the older plant or maybe just the affected leaves?
<I'd leave all... the calcium et al. in the existing thalli/pads will add to the system>
I have read they do not like being pruned though...or should I wait for the little ones to grow a bit bigger first?
Inserted a pic below. Any feedback is appreciated as usual.
-LED 89w par intensity up to 700, lights on for 7 hours
-2 returns @ 266 gal each
-1k icecap gyre at 700 gph peak
-SG 1.025
-Am 0
-Nitrite 0
-Nitrate <10
-Alk 10
-Calcium 475
-Mag 1400
<These are certainly fine, in fact, a bit high. I'd allow the [Ca] to drop to about 400 ppm, the [Mg] to about three times Ca>
-Test bi weekly with Salifert & dose Seachem reef builder, calcium, & magnesium.
-10% weekly water change with Red Sea
-I only feed frozen twice a week (half cube typically) with a small broadcast of zooplankton (1-2ml), pellets 4 days, and no food on water change day.
-skim aggressively with a Aquamaxx HOB 1.5
<What is the temperature here? I'd keep in the upper 70's F max; and do you have measurable phosphate? Necessary. Bob Fenner>

Re: Early Autumn for Halimeda?     8/16/18
Hi Bob!
<Hola Dani>
Just tested my phosphates and nitrates too just in case. Phosphates are undetectable and so are nitrates.
<... mate; all life we're interested in need both. This IS the likely cause of failing health here>
It’s summer here in Florida, so my tank peaks at 84F and averages 82F during the day at the moment. I don’t have a chiller so the best I can do is run lights at night and at that time lower the a/c.
<I would cut the lights back, scoot the top/cover a smidgen>
Last week I did remove my chemical filtrants because I felt it was making my water “too clean”—possibly too soon to really make a solid judgment but from this base test, it may show I was right. I reduced my weekly water changes to 10% from 25% as well.
<Good moves>
I do have other macros in the tank including: Codium, shaving brush, blue Ochtodes, Caulerpa prolifera, Padina, an unidentifiable Rhodophyte, and dragon’s breath—all of which are flourishing.
<Ahh; well, these may well be outcompeting your new/er Halimeda. B>
Dani ��
"Adversity is merely fuel for virtue~"
<Not necessarily, or always>
Re: Early Autumn for Halimeda?     8/16/18

Good evening Bob!
<Good morrow Danila>
Well, after listing and realizing how many macros I own, I had a feeling you’d say it was possibly being outcompeted. So ironic—for months I was battling nitrates and phosphates and now I’m one of those looking for them, lol.
Well, do you think it wise to wait a week, or few perhaps, to see how the lack of chemical filtrants and reduced % of water changes impacts the tank?
<Yes; this is a sensible approach>
I’ve done further research on Halimeda so I know what it looks like when it’s about to explode spores...appears white and with green fuzzies.
<Good desc.>
I’m not sure my nano tank would handle the ammonia that can build up after they go sexual?
<Mmm; not much ammonia/protein involved here. Likely if your system is fine/balanced, you have sufficient filtration, circulation, and likely "caught" the event early on you'd be fine>
I feel I am dancing on a fine line the way it looks. Today it actually looks a bit better and the babies are growing like Aiptasia went out of style.
If I still have zip phosphates and nitrates after observing, I’d like to maybe switch to biweekly, or less maybe, water changes before trying to dose stuff just to raise nutrients.
<Mmm; well; I wouldn't purposely "add nutrient/s", but maybe feed your livestock a bit more>
As always, appreciate you and your team’s advice. You all have been helping me since I started with a 45g that ran with a penguin filter (LOL!) over 10 years ago!
<Glad to find you have stuck with the hobby. Can be trying at times eh? Bob Fenner>

Quarantine Chaetomorpha 4/20/10
Hi there,
Recently I would like to acquire some Chaeto algae to help control the nitrate level in my 180gal FO tank, my question is can I quarantine the Chaeto in a 2 litre gold fish bowl without any circulation or air stone for 1 month?
<I think you should be okay here... given the temperature in the area doesn't vacillate much, you keep an eye on the water for obvious troubles like too much evaporation, a film collecting on top. Would be better by far to have/use a simple quarantine/acclimation/treatment tank... with a heater, some sort of filter, circulation and simple lighting>
I plan to put the algae in my sump which currently have a 6 inch sand bed.
<Welcome. Bob Fenner> 

Maidens Hair Problem  12/30/07 Hello Crew! <Vadim> Thank you very much in advance for your advice... I am very new to the hobby and WWM had been a great deal of help already. <Ah, good> I have a 5-months old Red Sea Max (34g) with about 3" of substrate (AragAlive live sand) and ~35lb of live rock. I made some adjustment to filtering media by adding a Poly Filter pad and replacing activated carbon with ChemiPure Elite. <Okay> The population is 2 false p. clown fish, 1 cleaner shrimp, 1 Mithrax crab, 3 dwarf feather-dusters, 1 Hawaiian feather-duster, 9 blue-legged hermits, and a variety of snails: 3 Mexican Turbos, 5 Astrea, 6 Cerith and 3 Nassarius. <A lot of snails, hermits> Water parameters seem fine: SG: 1.025; Temp: 79F; Ammonia & Nitrite: undetectable; Nitrate:2.5ppm, pH:8.2, Alkalinity 2.8Meq/l; Calcium:380ppm. I change 15% of the water weekly; top-off with RO/DI only. About 5 weeks ago I have added a piece of live rock with Maidens Hair growing on it. Everything was fine for a while, it look great waving in the flow, but about 2 days ago the tips of Maiden's hair clumps became a lighter shade of green and another two days later the whole clamps of it turned white. Can you give any insight into what can be the problem? Thank You! VMK <This algae died... perhaps a lack of nutrient, maybe light... See WWM re Chlorodesmis, Green Macroalgal culture. Bob Fenner>

Chaetomorpha vanishing act... Rate limiting rxns  12/20/07 Thank you for your help in advance. My Chaetomorpha just disintegrated in my refugium and I'm talking a whole 30 gallon of it so thick you couldn't even put your hands through it. It had been growing for about 6 months, and I would give handfuls of this stuff away to people because it grew so fast, now its gone. I reached in the refuge for some to put in my display for a snack for my tangs and nothing. I have a 120 gallon with a 30 sump and 30 refugium. 3 HQI's over display and opposite PC over refuge. Lighting is obviously fine since it grew like a weed for 6 months. Lots of water flow with 2 dart pumps (closed loop), I run a calc. reactor, carbon and SeaChem PhosBan. <"This" may have been "it"> nitrates, nitrites, ammonia always at zero, <Or these lacking...> calcium 400, Alk 4. Temp stays around 81.5 day and 79 night. use only RO water. I do 5 gallon water changes every Sunday and only additive that I use is SeaChem iodide. This is an Acro tank and have changed nothing, I like things consistent and stable. A couple of days ago, I noticed some red slime starting to form, so I figured it must be time to change my PhosBan. I run continues and change every 30 days. I was about 2 weeks behind. Now a few days later, its gone! What happened? <Bottle necking... loss of an essential nutrient... HPO4... Like cutting off something critical to your life... oxygen let's say... Bob Fenner> Thanks Brian
Re: Chaetomorpha vanishing act 12/20/07
Also, a continuation of the email I just sent, my water is now very cloudy and my skimmer is overflowing and bubbles everywhere. I'm assuming this is all of the chemicals being released by the algae. <Yes> I'm afraid to test to see what just got released. What should I do? <A massive water change with what water you have pre-made, stored... perhaps the addition of in-line chemical filtrant/s... e.g. activated carbon. If necessary, the removal of purposeful life to another stable system. Bob Fenner>

Merman's Shaving Brush alg. hlth.  -- 06/17/07 Hello WWM crew, It has been some time since I have needed to call upon your expertise. I have recently obtained a Sea Cactus and "Shaving Brush" plants, newly planted 24-48 hrs ago. They have lost their green color and the shaving brush is losing it's "brushes". Is this normal until they are established? Water qualities well within suggested limits. <Mmm, some color loss is to be expected, but not the "brushes"... this algae is dying or dead...> If not normal, what to do? <Should have isolated, acclimated to the tank water quality, conditions before placement... Now? Wait, remove if it dissolves outright> Thanks again....you have saved our lives many times when we were first starting with our nano tanks...I have faith again. Sincerely Stephanie <Bob Fenner>

BLEACHED CHAETOMORPHA 4/1/04 Hi gang: I have two large-ish collections of macro algae sharing a common sump, aside from a 105 gal main reef.  One is for a sixty gallon tank, with bright light, a rose BTA, and a pair of clownfish -- all doing well. In my fishless refugium, I have a mass of Chaetomorpha that's gone from a pound to ten pounds in the past several months.  High growth rate due to excess nutrients in my system. . . I've added a DSB which has now matured into a great nitrate-processing machine, but this growth was mostly during its 'break-in period'. I was dosing Kent iron, but my supplement bottle was over a year old. . . and when the Chaeto started paling I realized the rusty color of the supplement probably meant the iron was no longer bio-available. New growth on my Ulva (lettuce) in the display tank began paling soon there after.  I ordered a new bottle Ken iron. . . which is decidedly paler/yellower in color (a good thing, as I understand it). <I'm not sure about the color of the supplement vs. bioavailability. Certainly more red/brown is more oxidized.> My question is: Is the 'pale' Chaeto likely to generate more chlorophyll and 'green up' over time, or should I cull the paler growth (which is most of the total) and start over? <I suspect that the "bleached" parts won't recover.  Also, considering how fast this stuff can grow and that it extracts nutrients faster while growing, I would hack out all of the pale stuff.> Water quality is otherwise good. . . Nitrates 0, Nitrites 0, always some ammonia in my system though. Ph varies from 8.1 @ night to 8.3 during later 'daylight' on the reef. <I'm suspicious of the ammonia reading and would suggest verifying this with another test kit.> Same question goes for some red calcareous algae I've managed to bleach. . . but this was because I hadn't read the WWM FAQs. . . which outline how little light the reds seem to want relative to green (and even brown) algae. <Coralline algaes go through many changes based on lighting, water movement, alkalinity and other conditions.  Others will move into the empty space.> Lest you think I'm busy abusing various marine plants, I've got small quantities of about a dozen other species that are doing great. Codium, Halymenia, red Dictyota, yellow Dictyota, red grape, etc. (No Caulerpa though!) Thanks in advance for any help on this. Chuck <Getting a head start on the burgeoning macro-algae craze!  I suspect that many will soon share your interest in these beautiful and useful algaes.  Best Regards, Adam>

Dying Halimeda 07/15/03 <Hi, PF with you tonight> I purchased a reef tank that had been established for two years. The tank had plenty of Halimeda plants growing in it. I use to use synthetic salt water but now converted to ocean salt water from a local source. The problem that I am having is that the Halimeda is dying. I set up a refugium and planted Halimeda in it along with other algae plant. All the plants are doing very well with the exception of the Halimeda. This same problem is occurring in the tank, all plants are prospering with the exception of the Halimeda. I added extra iron and calcium but still the problem exists. <Well, in all honesty switch back to the synthetic salt mixes. There's plenty of public aquariums that use them (like the National Aquarium in Baltimore), and if it's good enough for them... From what I have read and been told (by the likes of Bob, Anthony, JasonC, and others) sterilized seawater generally doesn't perform as well in a tank as does a mix. I'm not a chemist so I can tell you why, but for example, it loses it's buffering properties a lot faster.>

Bleached Turtle Weed Hi Bob, Hope you and the rest at WWM have had a wonderful and merry Christmas.   <It was a bit hectic, but all in all a good holiday season.  Hope you had a good one yourself!> I hope you can give me some advice to my query soon, I had bit of a hair algae problem in my tank that seems to be improving, with some vigorous water movement by addition of 2 power heads and a new skimmer. Recently I bought some Chlorodesmis fastigiata turtle weed which was a healthy green colour, I put it into my tank it is about 8" away from my fluorescent tubes, yesterday I noticed it has started to bleach and is getting white in colour, the temperature in my tank is a constant 26 Deg, rest of the corals and fishes are doing well.  Is there any way I could reverse this process or is that patch of weed doomed? <I would suggest moving it farther away from the light source.  I think it's getting a bit too much light than it's used to in wild.  If you move it to a more shaded area of the tank or at least farther from the lights then I should expect for the bleaching to at least slow, but hopefully for the turtle weed to come back to it's natural emerald color.  Surprisingly not a lot of info is found on turtle weed, but I'm sure once this catches on as a great natural filter for water more info will become available.   http://people.hws.edu/fieldguide/show.asp?ID=160 That is at least one nice site with some basic info on it.> Wishing you and the crew a very happy and prosperous new year. Compliments of the season. Jorell <Hope you and the tank have a great year as well. -Magnus>

Chaetomorpha help The problem/questions: I'm having a problem with Chaetomorpha slowly dying. Small sections are turning from dark green to clear and those clear sections eventually go limp and dissolve or break away. I have tried placing the colonies at different heights within the tanks but with no improvement. Gracilaria in this same system is growing rapidly. Ochtodes is doing well but growing slowly. Micro algae exists, but is kept under control by snails and other tiny invert grazers to the point where I no longer need to clean the glass. The macro algaes are separated by a reasonable distance, but is it possible these are conducting some sort of chemical warfare?  <Yes> I chose these varieties because I believe they are less noxious then most. What is your opinion of chelated Iron in a marine system? <Generally ferrous matter is not rate limited in marine systems, but it does little possible harm to add it> I have heard anything from definitely not to it's a requirement of macro algae. I have started adding Kent Marine Iron supplement for the past month, but that doesn't seem to make a difference one way or the other so far. The setup: The system is 3 months old consisting of a display and refugium with several types of macro algae. It is currently fishless but has two L. debelius and a good assortment of micro-fauna. Both tanks use compact fluorescent lighting - ~4w/gal in the display and ~5w/gal in the 'fuge. The lights are on 10 hours in the display and 18 hours in the 'fuge on a reverse schedule.  Everything is growing well except the Chaetomorpha. There is a fist sized colony in the display directly in the path of one of the returns; it tumbles freely. The second colony in the 'fuge is much large and is stationary with moderate water flow; it rests on a 2" bed of Kent Bio-Sediment. Water parameters: Temp: 80-82F Specific Grav: 1.022-23 pH: 8.2 KH: 110-160 mg/L Calcium: 440-520 mg/L <This is a bit high... I would let drop to about 400 ppm> Ammonia: undetectable Nitrate: undetectable Nitrate: ~5 mg/L Phosphate: undetectable Silicate: undetectable Free Iron: undetectable Chelated Iron: 0.1-0.25 mg/L <I strongly suspect that the Chaetomorpha is indeed being "deselected" for biologically in your system... and would either move it to some other separate system, or let it go. Bob Fenner>

Dying Chaetomorpha... needs more water flow? 1/29/05 Hey guys. Just a quickie for ya, if you don't mind. I have an upstream refugium with a few bundles of Chaeto, and for some reason it is turning white and dying off.  <the most common reason is a lack of water flow. Chaeto is very hardy with regard for lighting (5 watts per gallon will do)... but it is very needy for water flow so strong that it stays tumbling> I run a system with a fairly high nutrient load, since it is a softie tank, so I am a bit confused as to the issue here. I have a 10K regular wattage fluorescent bulb, run opposite of my display tank. Is it a possibility that Iron is depleted too rapidly in my system? <not likely the problem here> I dose b-ionic daily, and it lists iron as one of the trace elements... but I am wondering if I need to supplement further. At any rate, I though Chaetomorpha was not an algae that dies off as it has been, so I am a bit confused.  <correct... it is quite hardy and not prone to events of sexual die-offs... particularly if/when you have been harvesting it regularly> Any speculations would be greatly appreciated. Thanks! <this is a common question and problem... most always a lack of water flow. Apply enough to make the Chaeto ball tumble. Anthony>

Halimeda plant I currently have a good sized Halimeda plant within my 135gal reef tank. Short of listing all the variables of my tank, this plant has been in there and steadily growing from just a nub for the past 8 or so months.  All of a sudden, pretty much overnight, most of the entire plant turned white and lost all pigmentation.  In reading various articles on this, I do see that this is something that does happen, but my question is should I remove the entire plant, or let it break down the calcareous skeleton that was left behind.  It appears that right now, it has not had any noticeably harmful effects to my tank or its residents, but it did kick my skimmer into full action. <I would suspect a parameter change that affected the Halimeda and increased skimming, maybe not the Halimeda itself. Regardless, I would test tank param.s completely including calcium, magnesium, Alk, pH, ammonia/nitrites/nitrates.  Usually calcium/Alk related, perhaps photoperiod, or perhaps a nutrient/ammonia spike or low RedOx. How long are lights on? Should be about 12 hours. You'll need to test to resolve any possible problem. I would trim back to base and resolve any parameter out of norm. It will probably grow back.> I have yet to test the levels of things, and if I notice a rise in anything unusual, I would obviously take care of it at that time. <Better do this ASAP> Please let me know any recommendations on this one.  Thanks. Andy <Hope this helps, Craig>

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 -- >>

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>

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