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FAQs about Blue-Green Algae Identification 3

Related Articles: Blue-Green "Algae"/(Cyanobacteria), Embracing Biodiversity, Green Algae By Mark E. Evans, Green Algae, Green Algae 2, 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, Diatoms, Brown Algae,

Related FAQs: BGA Identification 1, BGA/Cyano ID 2, BGA/Cyano ID 4, & Controlling: BGA/Cyano, Green Macro-Algae ID 1, Caulerpas, Green Macro-Algae 1, Green Macro-Algae 2, Green Macro-Algae 3, Green Macro-Algae 4, Chlorophyte Behavior, Chlorophyte Compatibility/Control, Chlorophyte Selection, Chlorophyte Systems, Chlorophyte Nutrition, Chlorophyte Disease, Chlorophyte Reproduction/Propagation, Marine Algae ID 1, Marine Algae ID 2, Marine Algae Control FAQs II, Marine Algaecide Use, Nutrient Limitation, Marine Algae Eaters, Culturing Macro-Algae; Red/Encrusting Algae, Green Algae, Brown/Diatom Algae,



New Print and eBook on Amazon

Marine Aquarium Algae Control

by Robert (Bob) Fenner

Alg. ID, likely BGA  10/15/13
Hi,  I know this is not the greatest picture..., but can you tell me what type of Algae this is.. it seems to be fleshy like and grown really fast..... I have had my tank up for years and never had this type and now it is showing up everywhere... how do I get rid of it and what is it????
<... do you have a microscope? Is, does it feel really slimy? This is highly likely BGA, possibly a sponge plus...>
Thank you for all your help and any products I can use to treat for this...
I have just fish, shrimp and hermit crabs in the tank with live rock...
<... none of the above will eat this. There are quite a few FAQs files, articles on WWM for free for you to peruse. Otherwise I do have a new eBook out on Amazon re marine algae, control in aquariums.>
Thank you for your knowledge and great information to all on the crew.
Paul
<Welcome! Bob Fenner>

Reef Tank Fuzzies 9/12/11
Hello Guys,
<Babak>
I have been having quite a time trying to figure out what's growing on one of my coral skeletons, it resembles green hair algae yet has no color or is perhaps white or grey and seems to branch in some places.
<Mmm, digitate... likely is an algae of some sort... Really need to look at under a lowish power microscope to tell for sure>
Does anyone have any idea what this is? I was told that it may be some type of sponge but I don't feel
that's right.
<Not likely a sponge if very flexible... Algae come in all colours... yours is likely a blue-green/Cyanophyte... See WWM re, including limiting nutrient, other means of control. Bob Fenner>
Thanks,
Bob

Undying Algae, BGA 6/5/2011 /RMF
Hey Guys,
<Marc>
Second time writing in, last time was about 4 years ago. Your support and recommendations were great then, hence why I'm coming to you again!
I've had a 90g tank (20g sump) setup for about 2 years now. Recently its gone through lots of changes as I just couldn't get my nitrates/phosphates down to reasonable levels. I removed all my bio-balls in the overflow, and removed two large chambers of crushed rock in my sump. This improved things greatly, but parameters were still way out of whack. I then removed lots of rock (I realize now I had way too much) and re-positioned everything for much better flow through the structures.
<Good moves>
I've also been using the vodka method for 3-4 months now with fantastic results. After finishing all this re-work over the past few months, my parameters are as follow:
Temp: 26 C
Salinity: 1.025
Ph: 8.3
Alkalinity: 10 dKH
Calcium: 500
<Too high... see WWM re>
Ammonia: 0
Nitrite: 0
Nitrate: 0
Phosphate: 0
<... NO NO3, HPO4?>
The tank is 24" deep and running 2 x 250w MH (14k) for 10hrs a day. Tanks isn't too far from a window, so it does get some subsidiary light in the morning before the halides turn-on. Not too much though. The substrate is about 3" deep. I have about 40+ times water flow. Sump pump is 5,000L and 13,000L total output in display. All water comes through a RO filter.
Skimmer running 24/7.
On to the problem, about 6 months ago; Cyano (I think)
<I do too>
was introduced into the tank.
<Is omnipresent...>
The whole tank was regularly covered in it in short time. I was siphoning and scrubbing my rocks to keep it clean weekly. At the time I wasn't too surprised as the parameters were all out of whack. However, I have now got everything in pretty good condition, yet I still have this same algae growth. It appears different now (in fact, before I started making all my changes) and is perhaps 2 different types of algae. I'm just totally at a loss now at what to do and what I have growing in my tank.
<Read here: http://www.wetwebmedia.com/bluegralgae.htm
and the linked files above re BGA, control>
There appears to be a purplish film on the glass, which wipes off with no problem. However, there's also a browner/redder algae growing on the rocks.
This is the stuff that takes over the tank...I'm not sure what either is.
<... requires microscopic examination to be sure, but these are all likely BGA>
My guesses were towards Cyano, diatoms (except they never seem to cycle out) and Dinoflagellates. I've attached some pics which show the brown and purple growths, please let me know your thoughts.
Regards,
Marc Steeb
<Write back after reading if you have further questions. Bob Fenner>
Undying Algae/Algae Control/Vodka Dosing 6/5/2011 /JamesG
Hey Guys,
<Marc>
Second time writing in, last time was about 4 years ago. Your support and recommendations were great then, hence why I'm coming to you again!
<Great!>
I've had a 90g tank (20g sump) setup for about 2 years now. Recently its gone through lots of changes as I just couldn't get my nitrates/phosphates down to reasonable levels. I removed all my bio-balls in the overflow, and removed two large chambers of crushed rock in my sump. This improved things greatly, but parameters were still way out of whack. I then removed lots of rock (I realize now I had way too much) and re-positioned everything for much better flow through the structures. I've also been using the vodka method for 3-4 months now with fantastic results. After finishing all this re-work over the past few months, my parameters are as follow:
Temp: 26 C
Salinity: 1.025
Ph: 8.3
Alkalinity: 10 dKH
<I shoot for 7dKH.>
Calcium: 500
<Too high, dKH problem lie ahead maintaining this level.>
Ammonia: 0
Nitrite: 0
Nitrate: 0
Phosphate: 0
<Where is you magnesium at?>
The tank is 24" deep and running 2 x 250w MH (14k) for 10hrs a day. Tanks isn't too far from a window, so it does get some subsidiary light in the morning before the halides turn-on. Not too much though. The substrate is about 3" deep. I have about 40+ times water flow. Sump pump is 5,000L and 13,000L total output in display. All water comes through a RO filter.
Skimmer running 24/7.
On to the problem, about 6 months ago; Cyano (I think) was introduced into the tank. The whole tank was regularly covered in it in short time. I was siphoning and scrubbing my rocks to keep it clean weekly. At the time I wasn't too surprised as the parameters were all out of whack. However, I have now got everything in pretty good condition, yet I still have this same algae growth. It appears different now (in fact, before I started making all my changes) and is perhaps 2 different types of algae. I'm just totally at a loss now at what to do and what I have growing in my tank.
There appears to be a purplish film on the glass, which wipes off with no problem. However, there's also a browner/redder algae growing on the rocks.
This is the stuff that takes over the tank...I'm not sure what either is.
My guesses were towards Cyano, diatoms (except they never seem to cycle out) and Dinoflagellates. I've attached some pics which show the brown and purple growths, please let me know your thoughts.
<I'm thinking this may be due to your vodka dosing and is/can be a downside with this method of dosing. Problem with dosing vodka is the rapid production of bacteria within the entire system which in turn feeds algae.
Dry vodka dosing via carbon polymer pellets is a much more desirable method as the bacteria are limited to one area, the reactor. The output from a reactor that is used for dry dosing can be directed toward the skimmer's intake pump which will reduce the surplus bacteria a good deal. Two Little Fishies (Julian Sprung) has a nice inexpensive reactor (35.00) that works very well with the carbon pellets.>
Regards,
<Ditto. James (Salty Dog)>
Marc Steeb


re: Undying Algae, BGA id f', now control 6/5/2011
Thanks for the reply, confirms what I suspect. I'm still a little confused on how to treat this though. I read through the article you recommended and it seems to focus around manual removal and filtration.
<... keep reading... competition, predation... preventative means of nutrient limitation>
If get down to it the recommendation is to control nutrients better. I always thought DOC's and nitrates/phosphates (nutrients) were essentially one in the same.
<One set includes the other, but not vice versa>
Get your nitrates/phosphates down to undetectable and you have little DOC's in the water...?
<The universe is more dynamic... it may well be that the BGA is/are taking up these readily>
With my current testing, nitrate/phosphate are at 0 ... so unless I'm wrong (wouldn't surprise me) DOC's should not be present.
<Guess again>
If I'm wrong, than DOC's need to be removed via another method ... skimming? My current skimmer's performance is rather erratic, to say the least. Perhaps time to upgrade.
<Maybe>
I received a reply from James (Salty Dog) on the previous email in which he proposed the vodka dosing was causing the problem due to overgrowth of bacteria.
<Can>
My vodka dosing has trailed off to a maintenance regime now and definitely has a large part to do with my low nitrates/phosphates. Do you think I should change something with the vodka?
<I suggest you read re on WWM. I would NOT continually use>
Thanks again!
<Welcome. BobF>
Regards,
Marc Steeb

Kalkwasser Drip location & Buffer addition 4/4/2011
Gentleman, <& some ladies> your willingness to share your experience, knowledge and ultimately your wisdom on this site has encouraged me to keep on when I had almost given up hope.
<Ah, good>
Years ago I had a successful freshwater tank but always was drawn to the reef side of the store. 2 years ago decided to give it a go, I have read & read & read on so many sites on so many nights into the wee hours on how to build, stock and maintain a reef tank in my house. Small price for the opportunity to daily see the splendor of a coral reef in ones own home.
<I do concur w/ you>
For to have a bit of a reef in my home is a richness that many a king would have given a ransom for in early times. The despair I was feeling was because I was not getting it -- mostly the chemistry. Chemistry and retention are not my strong suits and I know I have messed up on my parameters a bunch of times.
<"When, where in doubt, trouble... change water">
But the 'visual' of the solutions offered to many an issue brought to the talented staff of WWM has me going in the right direction for sure. Thank you so much. I will spend a lot more time reading and trying to understand before I request your time for my questions but a couple that are very basic but I am just not confidant in what I think I understood. My system is outlined below: My battle, a ph that is always low and a carpet of brown/red hair algae that I just have not been able to control.
Drilled 36x18x24(h) w/3'DSB (Southdown),
<Mmm, I'd add an inch here... can be mixed in or will be in time... something fine, aragonitic>
55lbs LR, 2 x 175w Iwaki MH (6&6hrs), 2 x 96wVHO actinic (9hrs)
36g sump w/ 8g fuge w/ return pump fed spray bar, 3'DSB (Caribsea medium), 20lbs LR,
20g frag/quarantine w/Aquaclear 200, + return pump fed spray bar , LED's
90g total volume, 6g weekly WC
Flow of 620 gph CL + 580 gph return (combined into OM4 for 1200 gph main tank flow)
Euroreef RS80, Rowaphos & Matrix carbon in 2LittleFishys reactors
<Mmmm>
DIY chiller, DIY Auto TO w/RODI fed to DIY Kalk reactor
9.5dKH (Elos), 480Ca (Salifert),
<Too high... I'd settle in the low 400's>
7.7--8.0ph (Neptune & Milwaukee), .03 phos (Hanna), 1500 Mg (Salifert)
<And this, a bit too high... I'd allow to adjust or force through whatever supplementing practice/s you're involved in (limiting them)>
0, 0, 0 (Nh3/4, Nitrate, Nitrite -- all Salifert), 78-80 deg F
<... no Nitrate? This is telling. You very likely have an (entrenched unfortunately) BGA problem>
Yellow Tang, Clown, 6 Line Wrasse, 8 Chromis, 2 Yellowtail Damsels, 20 hermits, 2 Turbos, blood & cleaner shrimp, 20 snail
I am confused on these two subjects.
I have a beautifully simple, foolproof and reliable Top-off & Kalk reactor system that drips saturated solution into the return area of my sump after the main lights go off. I have read in several posts that Kalk should specifically be dosed into a high circulation area of the main tank. Without too many details of my system, this is really difficult for my setup. Aside from the risks to the return pump, is it acceptable to drip into the good circulation in the return section of my sump?
<Indeed it is>
And if my Alk, Ca and magnesium stay ok, do I just keep adding buffer (bicarb & Carb) until over the course of a few days I have incrementally raised my ph to 8.1 (min level) and then keep adding buffer (in the AM) to keep it there?
<... Please see the above. The too high Ca and Mg are hurting you here>
What is the time frame of the 0.2 ph up/down limit?
<Two days or so; not less>
Do I aggressively buffer up my WC water prior to introduction into the tank?
<I would not do this "too" aggressively, no>
If you get to these, thanks a bunch but thanks anyways for all you have already shared and invested in this great hobby!
John Stevens (2CC's)
<Do read here John: http://wetwebmedia.com/bluegralgae.htm
Doing what I've briefly touched on here... adding to the substrate et al., and what you can and do choose to supplant the BGA as detailed and very referred to in links therein, will get you to where you want to go. There are "other roads" (e.g. driving RedOx through an ozonizer)... but I'd take a "sailboat" mentality/route here rather than a "motor-cruiser". Questions, concerns, please write us back, Bob Fenner>

Re: Kalkwasser Drip location & Buffer addition 4/6/11
Thank you Bob. I will top off my DSB to a min 4" in the main tank with out mixing as it is already a "sugar" grain size and it is already 4" in some places, just less than 3 in higher flow areas, I don't think I should stir up the bed to/o much. I will blend in the same with the medium Carib sea in the sump to a 5" depth - maybe that will also help prevent the solidifying that this sand has shown itself to be prone to (the main tank is fluffy).
I also have a EuroReef RS135 on the way.
<A good product>
I think I need to skim more effectively. I was prompted to actually measure the skimmate production from my RS80 and even when its tea colored liquid I am only getting a cup every 3 days. I have had a hard time to dial it in. The skimmer is prone to intermittently go nuts and then overflow so I have it dialed it down to get the dark sludge. I clean it every couple of days - lots of sludge in the neck. I have concluded in my study that it can't hurt to upsize. ( side note - The instructions for cleaning the EuroReef very specifically mention that the neck must be dried after cleaning - any idea why).
<To facilitate the movement (not stall it) of the skimmate... so the bubbles "pop" in/near the top of the collection area>
I source the venturi fresh air from outside (Newer house, Canadian winters, dogs, 4 teenagers).
To clarify - the Matrix carbon and RowaPhos are in individual 2LF 150 fluidized reactors in series - Carbon first. Carbon is changed every 2 weeks the Rowaphos every three months (actually I recently bought a Hanna Phosphate tester so I will monitor the discharge for saturation).
In reference to the BGA - I will continue to browse the FAQ in the algae section but I don't think that BGA is the one I am battling.
<Seeing your photos included here, I am given to disagree>
I definitely have seen BGA shortly after the tank cycled. I have also had a variety of "Caulerpa" that spread like a hair net over all my rock (which is very porous). Both those died back when I upped the water changes and movement, started to dose Kalk and lowered the tank temp from 84F to 80F max.
<Good>
I have looked through many a book and website for a match to the current one (for a year). The closest I have been able to come up with is maybe "Acanthophora spicifera". If you could take a look at the pics I have attached and possibly comment on the variety it would probably make my browsing more fruitful.
<Mmm, maybe just the Caulerpa overgrown w/ the BGA. Again, a few minutes under a few hundred power microscope will get you this>
I concur with the "sailboat" approach. I will spend money on the right stuff when needed but at the same time my Dutch heritage (and 3 kids in University) is cause for frugal behaviour for this season of my life.
<Ahh!>
Once again, I am humbled and grateful that you and the crew are so willing to help me and so many others find their way to success in this wonderful hobby. Cheers! .....John
<Glad to share w/ you John>
Ps. Do I keep the string of emails intact when dialoguing with the forms or send a new individual one? (Never done this before)
<As long as the last is included, most of us most the time can remember pertinent data. Cheers, BobF>

red stuff in my tank 1/15/11
Hi,
<Hello.>
I got this saltwater aquarium off of craigslist a couple of weeks ago (it has been established for 2+ years prior to me getting it.) and about a week ago it started growing this red stuff on the sand. It usually almost covers up the whole bottom of the tank like a carpet with some bald spots, but I stir the sand up because I don't know whether or not if its good or bad.
<Not desirable.>
It makes little bubbles by the way if that at all helps you identify it. I have also attached a picture of some of it.
sincerely,
Andrew
<Tis BGA, see: http://www.wetwebmedia.com/bluegralgae.htm and the links at
the top for more information and how to approach this stuff. Scott V.>

Nuisance Microalgae 1/10/11
Hello WWM,
<Adam>
I have been having a rough time with an unknown algae for the good part of a year now, and have done what research I could and have not found any good info on this specific algae, so I am turning to you guys for some advice.
I have a 5 foot 120G, with a 60G fuge and 40G sump in the basement. Run 3 250w MH bulbs, 6.5 hours a day.
<This is a bunch of light, though I'd reduce the intensity, increase the photoperiod>
SG 1.026, temp 78, ca 440, Alk 7 [2 part
dosing], no nitrates or phosphates on my API tests (those I suppose they are there.) Flow from 2 Vortechs set a 100%, skimmer octo 200 recirc, and I run a Deltec mce 600. I run BRS carbon, and GFO.
<I would ditch the GFO... your photosynthates need soluble phosphate...>
I run your standard SPS reef tank, SPS grown fine, colour could be better, but no huge issues. I have a medium bioload, 2 clowns, 2 Lyretail, 1 2" hippo tang, 2 mandarins, midas blenny, royal gramma, orchid Dottyback, and a Multibarred angel.
The tank has been up for over 1.5 years now, and this algae has been stifling my liverock for probably a good year now. The algae is brown, definitely photosynthetic, since it wont grow in the shade, will grow in high or low flow, is hard to remove from the rock, and is extremely quick growing.
<I see this in your images... and from your descriptions, this is almost assuredly principally a Cyanobacteria...>
I feed very little to try and keep it in check, a pinch of pellets, or some rinsed Mysis everyday. I also have been dosing vodka for the past 2 months, I am dosing 5ml a day now. I cut back from 10ml a day, because my tank started produce a strong fishy smell. Since the vodka dosing, the Chaeto in my sump stopped growing, and has remained the same size.
<I'd keep the light on this green algae in your sump all the hours the lights are off on the main display>
No snails I have tried will eat it, I syphon it off the rocks when I do a water change and it is back in a couple days, it is impossible to clean it all off. The rock was dry Marco rock seeded with LR. I understand that if I were to control my nitrate and phosphate better it would have to die,
<Not ahead of your photosynthetic livestock, no>
however if I fed any less I do not think my fish would be healthy. I change approximately 30G of water every 2 weeks [Instant Ocean].
<Good>
I do notice that if I do not syphon it off the rock, it will grow until a certain point, turn black, fall off, and start the cycle again.
<Oh yes>
Do I do a three day dark period?
<Not of use here>
I am worried for my corals, though perhaps I shouldn't be. I am not sure what else I can do. Is there some magic animal that will eat it?
<Not likely, no>
I have even brushed the LR with a toothbrush to no avail.
Help please, what is this algae, and what else can I do?
<Is a BGA... a few paths to improve your situation are available... I'd take a few of them simultaneously. For one, look into improving your RedOx... also, I'd make the sump into a DSB w/ fine aragonitic sand...>
Adam
<Please peruse these articles: http://wetwebmedia.com/bluegralgae.htm
and http://wetwebmedia.com/SystemPIX/RedOx/RedoxPPTpres1.htm
and the linked files above. You can "win this battle", with a bit of understanding, application of tried/true technology. Bob Fenner>
Images--
http://farm6.static.flickr.com/5169/5341349931_937f60afe0_z.jpg
http://farm6.static.flickr.com/5129/5341348407_110514b9b2_z.jpg
http://farm6.static.flickr.com/5049/5341346897_b78b1b4df8_z.jpg
http://farm6.static.flickr.com/5168/5341345471_8f408bf2a3_z.jpg

Re: Nuisance Microalgae <<RMF>> 1/10/11
Hello WWM,
> <Adam>
> I have been having a rough time with an unknown algae for the good part
of
> a
> year now, and have done what research I could and have not found any
good
> info on this specific algae, so I am turning to you guys for some
advice.
> I have a 5 foot 120G, with a 60G fuge and 40G sump in the basement. Run
3
> 250w MH bulbs, 6.5 hours a day.
> <This is a bunch of light, though I'd reduce the intensity, increase the
> photoperiod>
>
-->It a 3 bulb pendant light, I could turn the middle bulb off for a
while
and see what happens.
<<I would>>
> SG 1.026, temp 78, ca 440, Alk 7 [2 part
> dosing], no nitrates or phosphates on my API tests (those I suppose they
> are
> there.) Flow from 2 Vortechs set a 100%, skimmer octo 200 recirc, and I
> run
> a Deltec mce 600. I run BRS carbon, and GFO.
> <I would ditch the GFO... your photosynthates need soluble phosphate...>
--> Done
> I run your standard SPS reef tank, SPS grown fine, colour could be
better,
> but no huge issues. I have a medium bioload, 2 clowns, 2 Lyretail, 1 2"
> hippo tang, 2 mandarins, midas blenny, royal gramma, orchid Dottyback,
and
> a
> Multibarred angel.
> The tank has been up for over 1.5 years now, and this algae has been
> stifling my liverock for probably a good year now. The algae is brown,
> definitely photosynthetic, since it wont grow in the shade, will grow
in
> high or low flow, is hard to remove from the rock, and is extremely
quick
> growing.
> <I see this in your images... and from your descriptions, this is almost
> assuredly principally a Cyanobacteria...>
-->I did have some red Cyano in the beginning, but I have no seen any in a
long while
<<... Please read where you were referred... NOT all BGA are red...>>
> I feed very little to try and keep it in check, a pinch of pellets, or
> some
> rinsed Mysis everyday. I also have been dosing vodka for the past 2
> months,
> I am dosing 5ml a day now. I cut back from 10ml a day, because my tank
> started produce a strong fishy smell. Since the vodka dosing, the Chaeto
> in
> my sump stopped growing, and has remained the same size.
> <I'd keep the light on this green algae in your sump all the hours the
> lights are off on the main display>
--->already on a reverse photoperiod
<<Okay>>
> No snails I have tried will eat it, I syphon it off the rocks when I do
a
> water change and it is back in a couple days, it is impossible to clean
it
> all off. The rock was dry Marco rock seeded with LR. I understand that
if
> I
> were to control my nitrate and phosphate better it would have to die,
> <Not ahead of your photosynthetic livestock, no>
> however if I fed any less I do not think my fish would be healthy. I
> change
> approximately 30G of water every 2 weeks [Instant Ocean].
> <Good>
> I do notice that if I do not syphon it off the rock, it will grow until
a
> certain point, turn black, fall off, and start the cycle again.
> <Oh yes>
> Do I do a three day dark period?
> <Not of use here>
> I am worried for my corals, though perhaps
> I shouldn't be. I am not sure what else I can do. Is there some magic
> animal
> that will eat it?
> <Not likely, no>
> I have even brushed the LR with a toothbrush to no avail.
> Help please, what is this algae, and what else can I do?
> <Is a BGA... a few paths to improve your situation are available... I'd
> take a few of them simultaneously. For one, look into improving your
> RedOx... also, I'd make the sump into a DSB w/ fine aragonitic sand...>
> Adam
-->My ORP is 474 at the moment,
<<Whoa! I would not have it this high>>
I do not think I could get it higher, I
suppose I could buy an ozone producer
-->I Only have a SSB in the display, what Ill do is make a DSB in my 60G
fuge, I think that should be sufficient.
> <Please peruse these articles: http://wetwebmedia.com/bluegralgae.htm
> and http://wetwebmedia.com/SystemPIX/RedOx/RedoxPPTpres1.htm
> and the linked files above. You can "win this battle", with a bit of
> understanding, application of tried/true technology. Bob Fenner>
> Images--
> http://farm6.static.flickr.com/5169/5341349931_937f60afe0_z.jpg
> http://farm6.static.flickr.com/5129/5341348407_110514b9b2_z.jpg
> http://farm6.static.flickr.com/5049/5341346897_b78b1b4df8_z.jpg
> http://farm6.static.flickr.com/5168/5341345471_8f408bf2a3_z.jpg
<<BobF>>

White patches on bare bottom tank... 7/27/10
Hi Doctor Fenner,
<Mmm, no doctorate, just Bob is fine>
It's been a long time. Hope you're doing well.
<Thank you>
I would like to ask you about something I have never seen before. Several white patches of different sizes (circles from about 2 to 5cm) appeared on the floor of a bare bottom reef aquarium. They are slimy to the touch. They seem to inhibit the growth of the thin layer of green micro-algae that are covering most of the floor except where the white patches are. My first thought was bacteria growth (or fungi?). I took a sample to observe under microscope. From what I could see, a fair amount of nematodes were present. Here are some pictures of what I could see at 400x. Could you please help me confirm what it is and if the owner should be concerned'¦?
Thanks for your input!
Regards,
Dominique Capelle
<Mmm, about the only thing I can make out in your images is what appears to be Oscillatoria... a Cyanobacteria... which might account for the slipperiness/slimy feeling... Read on WWM re this group of algae. Bob Fenner>

Re: White patches on bare bottom tank... - 7/27/10
Thanks!
But what about the color? Patches are whitish. I know Cyanobacteria can vary greatly in color, but is white a possible color?
Dominique
<Not usually, though can appear so... as well as black, red et al... I would not worry re this material... Likely a mix of Protists, bacteria, fungi... BobF>

Re: Live rocks turning dark greenish-black now sand covered by a greenish mat 4/19/10
Greetings ! O great knowledgeable ones,
<Where? They owe me money!>
About a month ago, I had mailed you regarding my rocks turning blackish green on me. Well now its the sand ! There is this mat of green algae-like stuff growing on the sand and on the rocks. It is cobweb like in structure.
Picture attached. Is this BGA ?
<Yep><<Mmm, maybe more Diatoms/Bacillariophyceans. RMF>>
Grows only in flow deficient places.
<Often the case.>
Should I reduce the photo period ?
<Light is not often the limiting factor for it's growth, phosphates and nitrates are bigger issues here.>
I employ a 20 gal monthly water change. pls do advice.
<More water changes.>
Also I noticed that there is no mention of Calcinus elegans in your hermit crab database. Wondering if it helps in the eradication of BGA.
<Of limited use here. See here and related FAQs for more http://www.wetwebmedia.com/bluegralgae.htm >
Thanks Blesson
<Welcome>
<Chris>

Please help serious algae problem -- 02/25/10
Dear WWM,
<Hi Gary>
These things are spread out of control and no LFS can help me ID what it is.
<It's an algae of some kind. Maybe BGA>
It is golden brown jelly-like stuff grows on live rocks and sand bed. Not like any other algae, they are super easy to brush off and floating around then settle down to different places. I have been siphoned they out everyday and they reappear the next day. My nitrate 0 and phosphate 0.05 on Elos testing kits. T-5 lighting ( 9 hrs daylight and 12 hrs actinic ).
<You are feeding this somehow. What are you adding to the tank as well as and apart from food? I have seen this before with people using vodka, or carbohydrate additions for nitrate control>.
Please help.
<Have you looked at all of the many algae control options as well?
http://www.wetwebmedia.com/algaeconMar.htm. There is a source in your tank, of something.... somewhere>
Thanks
<No problem>
Daniel
<Simon>

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