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FAQs about Diatom Algae

Related Articles: Diatom AlgaeAvoiding 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:  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 microscope's view of live and not diatoms.

Diatoms and "pods" questions 5/25/07 Hi Crew!  Hope you are all gearing up for what will be a great Memorial Day weekend!   <Yep, and IMAC next week so should be fun.> Again, I want to start by thanking you for your incredible web-site.  The amount of information you provide on a free-content site is truly amazing and I spend literally hours every day reading the articles and FAQ's.  My sleep has suffered terribly, but I have learned an incredible amount.  Thank you.   <Ok, but go to bed, you're staying up too late.> Ok, 55 gallon hex, a planned FOWLR, cycling for about 4 weeks now with about 50 lbs live rock and a 2 inch substrate of aragonite and live sand. <You are kind of in a no-man's-land here.  Usually looking for less than 1 inch or more than 3.5, depending on if you want a deep sand bed or not.> Running a Fluval 305 canister filter, <clean it often> 3 power heads (between filter and power heads there is about 720 gal/hour of circulation), and a Bak Pak 2R+ protein skimmer with no bio-bale. <Ok>  I was told the biological filter between by canister filter, live rock, and live sand would be sufficient. <Yep> Ammonia, Nitrite, Nitrate all 0.  Don't have calcium or alkalinity tests yet, but based on my readings here, plan on getting them in the near future.  No livestock in the tank yet...am trying to be patient!  <It’s everything in this hobby.>   Diatoms!  I have read here that diatoms are very common in new setups. <Yes>  I have had diatom growth now for about 2-3 weeks.  After reading your FAQ's on the subject, I have learned that the biggest likely contributor was the tap water I used to initially fill my tank. <Can be, depends on your water source.>  It sat for several days before adding salt to rid itself of the chlorine, but I have since learned there could have been silicates in the water that are contributing to the current diatom outbreak. <Possible.>  I will use RO water from now on when doing water changes, but have been reluctant to do the changes yet as I have heard you shouldn't do so when cycling a tank.  <Can slow down the process some.> Also, I have some red/brown macro algae growing from my live rock, which I have read will help. <Yes, although you don't want this taking over either.> My protein skimmer, however, (based on what I have read here in FAQ's) may not be doing it's job well enough.  Granted there are no fish in the tank so there is no food being deliberately added that would be contributing to the diatom growth or for the skimmer to skim.  That being said, even with the diatoms I am only getting a small amount of waste in the collection cup, and it isn't dark like I have read it should be.  Should I be concerned? <Not yet, but once you start feeding regularly and have some fish in there if the performance is the same you need to investigate why.>  About how long can I expect the diatom outbreak to continue, and can I start with water changes (given my parameters are all good) to slow the outbreak?  <Hard to predict and yes.>  Any other suggestions?  <Not really, seems like you are on the right track.> Last thing, I promise!  :-)  I have some sort of "pods" scurrying around in the tank.  I have read your FAQ's on the subject, and I will assume they are some sort of copepod. <Or amphipods.> Impossible to take a picture of because they are so tiny, maybe 1-1.5 mm in length with long antennae.  They do not look like the rolly poly isopods I have seen in photos here, but the little critters move so quickly it is hard to tell.  I see tiny little holes or burrows in the substrate against the acrylic wall of the tank...Am I right to assume the pods bury themselves here and come out at night after lights out? <Yes.> I guess I am just looking for reassurance that they are not the dreaded isopods, as I am getting ready to add my first fish. <Doubtful.> Also, is the presence of these copepods a sign of a healthy system? <Yes.>  I suppose I am also looking for reassurance I am running the tank well.   Thanks again for reading my novel and for your response.  Have a great holiday weekend! Jamie <Enjoy the weekend.> <Chris>

Adding liverock and brown algae 8/30/05 Hello Crew, <Hi Ginette, Ali here> I have a 55g flat back hex SW FO tank I have started on July 22 with 10 damsels.. I have one left. ( wish I would have found your site sooner) <Glad you found our site now!> I am at the point where Ammonia is 0 and Nitrate - 80ppm, nitrite- 5.0 ph 8.2 and a steady growth of brown algae. The LFS said not to add the live rock until my tank has 0 nitrites and to leave my tank lights off to slow down the brown algae. They advised me to make a 10% water change and get as much of the algae out as possible and turn on the skimmer. <Adding liverock now wouldn't be so bad. You must understand that most of the life on the liverock you will receive will be dead and die in your tank at this time, however the beneficial bacteria will survive and be the main source of your biological filtration.> My  Newb understanding of your mountains of informative material indicates that the rock should come before adding anymore stock to the tank and that it would help make sure the tank cycled properly..  Most of the articles regarding the Brown Algae indicated that this was a good thing and not something to stop in a cycling tank. So my question is can I add cured live rock to the tank now or should I wait?   <Keeping the lights off, or simply on for just a couple hours a day is not a bad idea. Common brown algae aka diatoms is not really a 'good thing'. In fact it is an indicator of high levels of unnecessary nutrients. The longer you let your liverock become established within your aquarium, the better.> Equipment:  2 Aqua Clear 50 power heads for the plenum ( every so often they blow out micro bubbles too) . 1 Fluval  204 ( I am rethinking this, it keeps blowing micro bubbles and I cannot find a leak), 1  Red Sea Prism Skimmer, 2 12 inch air stones, and I added a Zoo Med  100 -270 power head that rotates for circulation. Ginette Degner <Consider upgrading the protein skimmer and make sure you clean the ZooMed powerheads weekly as the 'sweepers' (rotating devices) on them tend to clog up and stop working in saltwater applications. Keep researching/learning and you should be okay Ginette! - Ali> Diatom Madness! 7/14/05 Hello Crew of WWM. <Hi there! Scott F. here today!> I will start by saying thanks for all the work you have put into this great site! I have found a lot of information in all the FAQ's and links here. <Awesome! Glad that you have enjoyed the site!> I do need some input here for a problem I have been battling for close to 9 months now. I have gone through the web and your site many times (read countless hours) and have implemented some ideas but to no avail. I would like to get your input if you can find some time please. I also regret that my message is going to be so long but I want to give you as much information as possible. <Very helpful!> All started with a 4 year old set-up of 110 g. that was actually running without any problems. In October of 2004 we up-graded to our "dream set-up" that has been a nightmare ever since! Here is the set-up (all is running as 1) Basement 220 g (6 feet long.) (3x 400W 10k and 2 VHO actinics) 3x Seio Powerhead 1500 1 PH 500 gph 3x DIY "sprinklers" 1 Maxijet for surface (all to say I do have a lot of movement in these tanks) 2 Yellow Tangs, 1 Regal Tang, 1 Purple Tang, 1 cleaner wrasse,1 A. Clarkii ,1 A. ocellaris,1 Lawnmower Blenny,2 Firefish SPS corals (very few, just started with frags donated),1 Heteractis magnifica anemone <Nice; but not a really good idea to keep with SPS corals, IMO.> On top 1st floor 125g (5 feet long): (VHO 1 daylight/ 1 actinic) 2x Seio PH 620 gph 1 Seio PH 1100 gph 1 P. Volitans (7 inches) 1 Blue Chromis (started with 3 but I guess the Volitans got to hunting, was the point <g>),1 Brittle Star, all softy type corals .Cleaning crew: Astreas, Nassarius, Turbos, Cerith in both tanks. Hermits in the 220g. The whole system as over 450 lbs of LR Equipment: 1 DIY Beckett-style skimmer,1 RS 626 skimmer (needle wheel type), NEW RO/DI changed all cartridges, and RO membrane less than 1 month ago again, and also added a 2nd DI to it (to get out more of the phosphates, see testing lower), ozone regulated by Aquacontroller to the ORP reading, UV light, refugium with Cheatomorpha,1 DIY calcium reactor,1 DIY Kalk reactor to the top off water. Running phosphate remover Tests of the system: Ammonia :0, Nitrate: 0, Nitrite:0,Calcium: 480, Alk: 8.0,dKH Phosphates: 0 (tap water: 1, after ro/di 0.05 with a Seachem test) Silicates: 0 (tap water : 4, after ro/di : 0 Seachem test also) pH: 8.2 day 8.0 night time<BR>Temperature: 79-80</DIV> Water changes every 4 weeks of 1 big garbage can worth. <Why not try smaller, more frequent water changes? Easier than you think, and a lot more beneficial, IMO.> Here is the problem: Diatoms!!!! All tanks, including the fuge, are covered in this really ugly brown algae. At first, I figured I was going to go through a small cycle because of the move from the 110 g to that massive system, but after 9 months, I do not think it is simply a question of waiting it out any more. So far we have added one skimmer (the needle type) thinking we need to remove more nutrients from the tank. We are getting some skimmate from it, so it was not a useless purchase. We added 1 Di to the RO/DI to insure we were not adding any phosphates or silicates to the system. We also put in a UV (to me it was a questionable purchase but my husband really wanted to add this one <g>) Am I missing something else I could do at this point? What I am really asking is: "How do I get rid of this ugly brown stuff?? " It is really bad. I have to spray the few SPS we have 2 times a day to ensure they don't suffocate under the diatoms. At this point, is it better to "spray" of my rocks (I can't even see the rocks anymore!) or just let the diatom go and they will eventually die off? I must say, in the close to 10 years we have been at this hobby, I have never seen this much diatoms and I am getting really tired of looking at what looks like a dirty set-up. Can someone give me any help here as to what to do more? <Well, it really sounds like you're doing everything possible to thwart the diatom problem. I am thinking that the source of the diatom nutrients is not in the water column. Perhaps it's in the substrate.> Should we:<BR>Vacuum the sand beds? <Only the top 1/2 inch or so.> Spray the rocks? <Not really a solution, IMO> Add any other equipment? <I think that you've spent enough already!> Let the diatoms do their thing (but how long)? <A possibility. Although I am an advocate of frequent water changes, it seems like there must be SOME silicate getting in there, probably in the source water, despite your test results. Perhaps, holding off on water changes for a while may cause the algae to "burn their fuel" and decrease in intensity. A worthwhile experiment, IMO.> Do more water changes? <Eventually...> Add any critters to the system? <Nope> Get out of the hobby? (not an option! ahaha) <Absolutely not an option!> Thank you in advance and keep up the good work! <I think that your best bet is to see if you really are bringing in silicate in your source water. Hold off on the water changes for a while, but keep working those skimmers. Let us know if you see any decline at all in the algae growth rate. Good luck and don't give up! Regards, Scott F.> Cleanup for Algae on Sand Surface Dear Crew: What biological controls do you recommend for cleaning brown and presumably diatomic algae from the surface of a sand bed? <Depending on the size of the system, some goby species, goatfishes... humans> I have a big cleanup crew comprised of Turbo Snails, Sea Stars and Red-Legged and Blue-Legged Hermit Crabs. Unfortunately, they haven't touched the brown algae on the sand surface. <Nope> I've read past postings on your website and I've noticed that tangs and brittle stars were mentioned in the past. I believe that tangs will only clean glass and live rock but leave the sand alone. I haven't seen anything regarding a specific type of brittle star to obtain for cleaning algae from the sand surface. I've just been told to avoid the green brittle stars. Any thoughts other than rolling up my sleeve to siphon?  <Mmm, the best approach... to utilize other algae as nutrient competitors... limit nutrient period... bear (and grin) the situation till the system cycles to favoring other types of life. Bob Fenner> 

Looking to acquire, culture Bacillariophyceans Our laboratory (Dr. Gordon, U of Manitoba, Winnipeg, Canada) is interested in acquiring the following diatoms to experiment on: Thalassiosira pseudonana and Phaeodactylum tricornutum Where can we purchase these and what are the costs involved? Are there special accessories required in addition to aquariums? Sylviane Kahane, Ph.D. <I'd try the Northwest and Southwest Fisheries Centers in the U.S. re these cultures... they will know where to find them, how to keep the cultures going. Bob Fenner >

Brown diatom slime algae Hi crew, <How goes it, M. Maddox answering and observing his new Maxima...> I currently have a 1 year old 55 gallon tank with 45 lbs live rock and EV 120 protein skimmer. I use a Spectra Pure 5 stage RO and DI filtration unit for my tank saltwater as well as for my fresh top off water. I use Instant Ocean Salt mix. <I love IO mix> I have plenty of water circulation and 2 VHO fluorescent lights (1 white and 1 actinic). <How much is plenty?  I have 1000gphj I have tested all water parameters (PH, etc) and all numbers are excellent with phosphates (LaMotte test kit) reading 0. <And you nitrates are?  Is your nitrate kit reading nitrate-nitrogen or nitrate-ion?> I have a major brown diatom slime algae problem completely covering all of my sand and now on the live rock. I have had this problem since the early days of the tank but it has just recently gotten out of control. I have no other type of problem algae in my tank whatsoever. I have done water changes, checked my Spectra Pure filter cartridges (all fine) and also recently tried P0 4 Minus (for phosphate removal) but nothing is working. My 2 clownfish, snails, peppermint shrimp, emerald crab are all fine and healthy but I just cannot determine the root cause of my brown slime algae problem. I only feed my fish a small amount of  food once per day. The only thing I  can think of as the root source of the problem is the Sandown Play Sand I have as substrate (silicates ????). If I replace this sand with some other substrate will this solve my problem ?? <Time for some nutrient export!  25% water changes weekly, and right before a water change stir up\rip out as much slime\algae as you can.  Also, make sure you have a LOT of water circulation.  Try using Seachem's Seagel (a combo of their carbon and phosphate remover) and if you suspect silicates they make a silicate removing compound as well.  Purchase some more snails to help eat what remains, and make sure your skimmer is pulling out 1-2 cups of coffee dark skimmate a week.  The only way to tell if your sand is releasing silicates it to put some in a glass of RO water and test for them after a 48 hr period...if they are leaching silicates, replace the sand.  A deep sand bed will help as well, to remove nitrates.  Make sure your pH is 8.3 (not 8.2!) and drip Kalk to help bring\keep the pH up and drive phosphates to the sand bed.  Drip at night to counter pH depression.  Good luck!  M. Maddox> Diatom Growing Tips - A Tutorial by Ryan Hey there!!! <Hi! Ryan with you> Quick question....I have been doing water changes in my mini reef aquarium with tap water. I have checked the tap water with my test kits for phosphates and nitrates (nitrates = 0 and phosphates = .1). The ph of my tap water is usually 8.0 and alkalinity is 8 (Long Beach Area). I have no problems with green hair algae as well as red algae but am having problems with brown algae (diatoms). The brown algae usually takes a week to come back which isn't a big deal because I clean the glass wall often.  However, the brown algae has encrusted the white parts of my live rocks and also the surface of my substrate. Since my tap water parameters are good, I am thinking it is silicates that is causing this brown algae...I have no test kit for it now. <Likely culprit> The nitrates in my tank are at 10-15 ppm. What is your take on this??? By the way, with only brown algae problems, will it harm my LPS corals, soft corals, button polyps??? <Algae on the tissues of corals can lead to problems- even death> I know that green hair algae is very dangerous but have not heard of brown algae being dangerous to reef tanks. <Can be, but less so than other variants> I want to start using different source water for top offs and water changes but not from a RO/DI unit since it is too costly and I am not a rich guy. <Many LFSs sell RO/DI water at a pretty reasonable price.>  I want to use drinking water....the ones that are 25-35 cents a gallon at a machine usually placed outside of a grocery store. Will this be a good source water??? <It's typically spring water, so no. Purified water will work with buffers.> I know that I have to buffer the drinking water before use but do I have to use a re-mineral product to put all the minerals back into it??? Or will the sea salt (IO salt) replace the minerals lost in the drinking water. <In theory>  If brown algae is no harm to my LPS corals than I will keep using my tap water. Thanks <A decent variety of small snails can help as well. Lots to research! Ryan>

Yes... another diatom question 4/14/04 Hi crew, hope all is well.  I have a 55g reef tank, now set up for 3 months.  I have had fish only systems before, but this is my first crack at a reef tank.  Everything seems to be doing fine, except for the diatoms.  I have read the FAQ's on this many times, and talked to other reefers also.  It is my understanding that if there is problem algae, it is there because of another existing problem.  I realize it is common for new tanks to run through a diatom stage, but it is getting out of control and I have been dealing with it for months now.  It has covered all of my rocks and sand.  I don't want to add any of that "algae killer" stuff to my tank, I want to find the cause of it and fix that instead. <If this is diatoms, there is nothing to worry about.  Algicides will not be effective and should be completely avoided in reef tanks.  Diatom blooms are not necessarily an indication of a serious problem.  They take very little nutrients to bloom and are very easily controlled.  They even have some benefits!  Read on...> My tank is as follows:  55g long w/ 35# live rock, 40# live sand/aragonite mix, AquaC remora skimmer (working great - about 1/2-3/4 cup every other day), penguin 330 w/BioWheel filter using carbon and phosphate filters, (2) 300gph & (1) 200gph powerheads.  I use RO/DI water, 5-10% changes weekly.  Ammonia & Free Ammonia=0, Nitrites=0, Nitrates=0 - 0.5, Phosphates=0.8, Ca=380 pH=8.2, dKH=9, SG=1.023, temp=78deg.  I have 4x65w power compacts, (2) blue & (2) white, which I have cut down to 6 hours total per day. <All sounds good, except for phosphate.  I would also raise the SG to 1.025-1.026 and eliminate the BioWheel filter.> The residents are - 1 yellow tang, 1 purple firefish, 1 yellow tailed damsel, 1 cleaner shrimp, 1 blood shrimp, xenia, elegance, full rock of green star polyps, open brain (on sand bed), Bali brain (on sand bed),  plate coral (on sand bed), Goniopora (on sand bed), leather coral, about 10 blue mushrooms, 2 feather dusters, 10 turbo snails, 10 sand sifting snails.  Is the tank overstocked with fish or corals (or both) for the filter system I have? <Probably not overstocked, but the yellow tang will quickly outgrow this tank.  I would suggest removing all but 2-3 Turbos and adding a few other varied grazers.  Astreas, Trochus and Ceriths are all good choices.  All eat slightly different algaes, so the diversity will help ensure that one of them is eating your pest variety.> I have recently read not to put any corals in the tank until about 6 months have passed. Is this maybe the cause? <Not at all.  This suggestion is for the benefit of the corals, not the system at large.> Also, I read on your site to find the source of the PO4 from source water or food supply.  Using RO water, it should be zero, right?  How do I check the source of the phosphates? <Feeding is generally the primary source of phosphate.  Phosphoric acid is used in the processing of carbon blocks for R/O prefilters, and some can and will leach significant amounts.  Do test your R/O water for phosphate to rule this out.> I use Pacifica plankton, Mysid shrimp, flakes & Cyclop-eeze for food for the fish & corals.  How do I know how much to give the corals when I target feed them, say, pieces of shrimp? <Very small amounts.  Do observe to see if they are actually capturing and ingesting the food.  Your elegance is the only coral you have that is likely to capture such prey, but will appreciate larger prey occasionally too.  Your open brain and plate should be fed larger (marble size) pieces of meaty food about once a week, at night when feeding tentacles are extended.  Soft corals and Goniopora will not capture this kind of prey.> Also, on an unrelated note, I have found 2 small glass anemones in my tank.  How do I safely get them out?  Thanks for your time and advice. Richard. <If they are not in a hole, they can be scraped from the rock with a knife.  If they are in a hole, you can inject them with concentrated Kalkwasser paste, peroxide or even very hot water using a syringe.  A new product called "Joe's Juice" works exceedingly well also.  Best Regards.  Adam> Light and Diatom algae II 10/7/03 I have no live rock or sand.  would you still recommend not to cut back on lighting? <you are truly missing the big picture here, my friend, and you will suffer from algae continuously if you don't get it. Nuisance algae has little or nothing to do with quality light... it is entirely about nutrient control. You have algae because you have nutrients under light... not because you have light. Please take the time to read more on this subject in our archives of articles and FAQs at wetwebmedia.com. Best regards, Anthony>

Light and Diatom algae 10/7/03 Hi, I have a 75 gallon saltwater F/O tank.  I have two non-related questions.  First, what is the maximum stocking capacity you would recommend for this size tank?   <depends on the fish. We cannot give an inches per gallon rule because, for example, ten 1" cardinalfishes produce far less waste than one 10" grouper. Do consider reading Robert Fenner's Conscientious Marine Aquarist book (a best-seller) for outstanding advice on such topics. Also, there is tons of free articles and FAQs archived in the wetwebmedia.com archives> Right now I have a pair of perculas, a pair of lemon butterflies and a dwarf angel.  I was considering adding a yellow tang and a flame hawk.  Would this be OK or should I just add one of the last two mentioned?   <both of the last two are reasonable to add re: bio-load> Also, while I am going through the diatom stage, should I reduce my lighting to less than 8 hours per day to help it get cleared up?  thanks, James <reducing the lighting may be harmful as it suffers the desirable photosynthetic organisms (on live rock/sand) that can in time outcompete the diatoms for nutrients. Please do not cut back on lighting. Instead, focus on better nutrient export like getting the skimmer to produce quality skimmate 3-5 times weekly if not daily... and controlling feeding (thawing and discarding all pack juice from frozen foods... algae fuel!). Best regards, Anthony>

Algae Problems, sounds like Diatomaceous bloom (8-23-03) 29gal marine; 8lbs live rock  8lbs bask rock (limestone/coral type); sand bottom. kH 10.0 pH 8.6 ammonia 0.25 temp 80F salinity 27ppm s.g. 1.019 CO2 0mg/Liter nitrate 20mg/Liter equip: whisper 10-20 power head w/ aerator Aquarium Systems protein skimmer Corallife 50/50 - on 11hrs a day  <First of all I would get the ammonia and nitrate down to zero by frequent partial water changes.> Fish: 1 small tomato clown 1 small yellow tailed damsel 1 small domino damsel 1 small mandarin goby 1 small scooter blenny 1 cleaner shrimp 1 small anemone crab  <Too many fish, the mandarin and the scooter are going to starve quickly in that small of tank with that little of LR.  See if you can trade these guys in to your LFS or something before they starve.> food:  1 cube frozen brine shrimp every other day  <Brine is almost useless as far as nutritional value goes.  Try some thing like Mysis and some of the formula foods.  More than 1 type of food would also be appreciated.> tank is 1 yr old, water changes with RO water - symptoms: brown algae coverage light to medium, skimmer doesn’t fill up very much (1/4 full every 2 weeks).  please help!!!!  can't take the algae anymore!!!!  what am I doing wrong? water clarity slightly foggy but still clear.  Sincerely,  Tyson <Try siphoning out the algae and see above.  Also do some reading on our site:  www.wetwebmedia.com Cody>

Diatoms? - 8/20/03 Hi, We clean our fish tank regularly but after a few days an orange film starts to appear on the gravel and ornaments. It becomes a dark rusty colour and we have to change the water again and clean the gravel. We have used algae treatment but this hasn't worked. What can it be? Thanks, Tracy <Hi. Tracy, are we working with Freshwater or Marine?  Freshwater it could be related to the food you are feeding, I have some messy eaters that leave a slight dusting of Hikari pellets all over my gravel, especially the side that is lacking in flow.  If it is salt water it could be diatoms which are brownish or the beginning of Cyano, before it gets thick and goopy looking.  I am not a big fan of algae treatments, aggressive nutrient export and manual removal should take care of it in time.  Use the google search tool and do a search for diatoms, and cyanoBACTERIA, you should find tons of info.  Best Regards, Gage>

Diatoms? - 8/20/03 Hi <cheers> We clean our fish tank regularly but after a few days an orange film starts to appear on the gravel and ornaments.  It becomes a dark rusty colour and we have to change the water again and clean the gravel.  We have used algae treatment but this hasn't worked.  What can it be? Thanks Tracy <it sounds like it could be diatoms... tanks that are overfed, overstocked, new or with source water rich in silicates all suffer from excess diatoms (a golden brown algae). You might try more aggressive chemical filtration like a better grade of carbon or a poly filter (from Poly Bio Marine). best regards, Anthony>

- Removing Diatoms? - Hi, I have a question about diatoms.  I have read that they usually appear right before or right after a tank is cycled.  I know the best cure is to treat the problem and not the symptoms.  And while I am trying to do that I was wondering if you knew of a reputable product that is effective in removing it from the tank?  <The only good algae cure/prevention strategy is to limit nutrients. Phosphate is a biggie but silicates are also said to fuel diatom growth. In new tanks (actually, in all tanks) diatom growth is to be expected and is healthy. I'd suggest adding some herbivores.>  Also, How long before this stuff goes away on its own?  <So long as you have some herbivores and you properly limit incoming nutrients, it should not get out of control>  After the tank is established for a while?  What kind should I expect after the diatoms?  <It usually succeeds to green algae if this is a new set-up. But don't worry, there will always diatoms making a home in your tank! -Kevin>   Thank you for your good help, James

- Scum between the sandbed and the glass, EW! -- Diatomaceous growth - Crew,  Tying back my last follow-up email to the original question -- now that we have narrowed this rusty appearance between the sand and glass to likely diatom, is there anything I can do to eliminate this ugly stuff? (horseshoe crabs are not working).  It is driving my cleaning-obsessed wife crazy! <Hehe, unfortunately nothing will really go down and clean that area. Pretty much everyone's sand bed looks like that, but if you want to avoid divorce you could stick some kind of an algae scraper down there to get rid of it. With the amount sand stirring critters in that tank, I'm not worried about disturbing the lower layers. Good luck! -Kevin> --Greg

Brown diatom bloom all over live rock in new tank. Hi guys, <Don today> I've read your website extensively as well as many books (including Mr. Fenner's of course !) on diatom blooms. All state that brown diatom blooms are common in newly set up tanks like mine (I'm 2 1/2 weeks into cycling process). My 55 gallon tank has 36 lbs of Fiji cured live rock which is totally covered by brown diatoms. I know the nutrients to minimize are phosphates, nitrates and silicates. <Yes, a natural progression. If you are not doing water changes, try changing 20-25% weekly with cured/aged mixed saltwater. Try to remove, by siphon/scraping as much of the gunk you can. Run filtration as well> My problem is figuring out where exactly these are coming from as I use Ocean Clear salt mix which "claims" to be phosphate free and I am using an Aquarium Pharmaceuticals Tap Water Purifier which "claims" to eliminate phosphates, nitrates, nitrites and silicate. <if they work, these are treating the symptom, not the cause. I’d save my money> Have I been taken in by the slick marketing on these products or can  these diatom algae nutrients be coming from my live rock. <Ummm, welllll yes and yes. Die-off from the rock is most likely the culprit here> I currently do not have any test kits to test my DI water for phosphates, silicates and nitrites which I suppose I should do but I keep spending more and more money on products that do not do what they " claim" they do !! <Good test kits are a must, eventually. LaMotte, Salifert are considered on the top end. Or, take samples to a Local Fish Store (LFS) and see if they can test for you. If for no other reason, knowing that ammonia, nitrite, and nitrate are all 0 indicates that the cycle is over. Keeping the pH constant and in the range of 8.1 to 8.3 is necessary. Calcium, Alkalinity will need to be checked if you plan corals. PS, I understand about the $$ thing. Get what you can when you can and use the LFS for tests in the meantime> Please help with my frustration if you can <I hope this helps. Be patient, add equipment when you can, research/read/learn in the meantime, relax and have fun! Don>!!!

Diatoms Hey guys, just wanted to run a couple things by you just for my own sanity.  I have a 125 FOWLR that is going through cycle (almost done) and the dreaded brown diatoms are on everything! It looks horrible. Even the few awesome pieces of LR that I bought are getting covered. I use Ro/DI water (tested low TDS 30 and 0 phosphate, 0 nitrite and 0 ammonia) and all my tank measurements are coming down to close to nil with the end of the cycle. I have not tested for silicates but from past memories I had the brown algae blues and remembered them going away much quicker than this. I have no living fish or inverts as of yet (other than hitch hikers), I am using the LR to cycle as well as the DSB with scoops from many friends reefs. I am also staying on a normal 12 hour light regiment and a reverse Refugium (38 gallon) lighting. I just wanted to double check that this brown explosion is part of what I assume to be a normal cycle process and that it will pass as it did in the past. I am guessing it passed faster in the past due to the smaller size of the tanks I dealt with. What do you think?   <sounds like everything is going well, if you are getting to the point where it seems they will never go away, then you are probably pretty close to the end of it.  Take a look at the link below for reassurance http://wetwebmedia.com/diatomfaqs.htm  > On another note, I am an avid DIYer and love using my hands. A major portion of all my tanks are done via DIY. I am looking to partake in a surge device of some kind for my next project. I would keep it to 2 gallon surges and possibly have on a timer for certain parts of the day. As I said above, its a 125 FOWLR. Would there be any pros or cons to using such a device on a FOWLR tank? Any suggestions on building one? Or should I move to a different project more suited to a FOWLR design? As you can tell, I am bored with waiting for the cycle and feel the need to tinker or something. ;-) <I do not have much experience with surge devices, I do not think it would be necessary on a fish only tank, but it sounds fun.  Check out the link below for DIY fun. http://www.ozreef.org/diy/index.html#SURGE_DEVICE  > As always, thanks to the awesome crew... Tim Reading, PA

Re: Diatom algae, light Thanks for all your help. I get the buffer situation and will get a buffer. I am still hazy on the lighting situation. You seem to be saying to increase lights now to burn out the bloom but it may make it worse by having longer lighting period? If I should increase the lights now what lights and for how long should they be on? Should I try to simulate dawn, early am, high noon, late pm and dusk? Thanks and sorry for bothering you guys <No bother at all! Yes, if you increase the photoperiod, the algae will then grow, but if you are controlling nutrient content/export, this will result in a shorter bloom but make it a little worse at first.  Since you have nothing to light that really needs it, you can play around, combining them as you wish, but once you acquire inverts/corals I would run the lighting 12 hours total. The lighting schedules, dawn, noon, dusk are a personal preference, but you can't replace photoperiod with intensity or vice-versa. Inverts and corals need 12 hours of proper intensity light regardless. Alternating light sources will not increase intensity, it will only shorten the intensity to one area. This is a deficit, not a positive. Some people use actinic lighting for a time before and after the main MH lighting to view corals like Hydnophora that fluoresce under this lighting, as long as the main lighting needs are met.  Craig>    

Diatom algae bloom I received 45lbs of LR from FFexpress a week later.  Since my tank is new i decided to go ahead and cure it under my regular tank conditions.  Its been 2 weeks w/ the rock and i seem to have a diatom algae bloom outbreak.   <Normal and expected> It has been like this for the past 4 days or so.  I have two skimmers on the tank, <Great!> circulation from powerheads and a Fluval 404 w/ biomedia and carbon running.  I have just upgraded my lighting to a 96w PC SmartLite 3 days ago.  Until then i was just using about 40w of regular fluorescent lighting.  My ammonia is dropping rapidly.  Will this algae fade away once the rock is done curing or is there something else that could be causing the problem? <Diatoms should abate in the coming weeks as your tank begins to stabilize. If you use RO/DI water it should help> My inhabitants are two yellow tailed damsels put in a week ago. <I really wish that aquarists wouldn't cycle the tank with damsels. If you have live rock the damsels aren't needed. The ammonia is really bad for them...In fact they probably won't survive. Sad...but true> thanks. Jason <You're welcome! David Dowless>

Diatom Explosion! Hello Team, <Scott F. here tonight> First, I want to say thank you for helping so many people. I ran across your site a week ago and have spent all my free time reading, re-reading and taking notes. An absolutely amazing website the best place for info I have found. <It really is a great resource for everyone. I'm thrilled to be a part of it!> Second, the history. I have had a 90 gal FOWLR (about 70 lbs. rock) tank for about 3 years with virtually no problems. All was well until about 3 months ago. I added 5 turbo snails to the tank (from a LFS I do not usually go to). Fish were 2 sm. blue tangs, 1 medium Naso, 1 medium lionfish, and a small puffer. <Kind of a heavy bioload for this tank, BTW> Within days my small tangs had spots that looked like ich, so I took them to the LFS I usually frequent and they said that they looked fine they had just been itching themselves on the rocks (HELLO!). So taking their advise I put them back in the tank and watched them. Within days everyone was infected. <I hope that you frequent that LFS less frequently, with advise like that. Shame on them!> I put all the fish into a QT tank and medicated with copper per directions and test kit. I think I was too slow in diagnosing because over the next two to three weeks all succumbed to the disease. Very sad. <It always hurts to lose an animal, but don't be too hard on yourself, just learn and don't make the same mistake again, and they will not have died in vain. Remember to quarantine all future purchases of livestock for a minimum of 3 weeks before placing them in your main system, ok?> In the mean time the main tank was left alone for the most part and the lights were left off for about 3 weeks. I have always wanted a reef tank and was considering purchasing a new tank to keep corals in so now I have decided to keep corals in this tank. It has been uninhabited, except for live rock for about two months. Due to my lights not on for that first month I lost about 50% of my coralline algae but it is coming back now. From the time I turned the lights back on I started to and continue to have huge diatom problems. My guess is that my tank is acting like a new tank and possibly could have recycled. <There is probably an overabundance of nutrients in the system that are contributing to the algae growth. Other considerations are your source water, which may have high levels of silicates, nitrates, and phosphates, all of which are contributors to the microalgae explosion.> I do 10% WC every two weeks. I started adding snails at the first sight of diatoms. I now have a total of 3 Mexican, 5 Margarita, and 4 Astrea. They can not keep up and I do not want to add more because they won't be needed when this clears up. It seems to be getting slightly better but still bad. Water is clear in the morning and rocks are not that bad, by mid day water clouds up and rocks get covered big time. Then by 7pm things start clearing up and the cycle starts again the next morning. My lights are on from 9a-9p ( 2x55w PC 50/50 and 2x35w normal output fluorescents). I was trying to agitate my substrate and dust off the rocks several times per day but I read that I need to let it run its course so I stooped. I have not seen any improvement except for this daily cycle. <If the water is cloudy due to diatom blooms in the water column, not just your agitating the substrate, then you have a definite need to take aggressive action in measuring and reducing nutrients. Do check those phosphates and silicates, too. Although not always to blame, your source water may be a major contributor. Consider using an RO/DI system, or purchasing RO/DI water to use as a base for mixing your salt. Your water changes are good, but you are at war! Increase to 10% per week, done in two small changes (4.5 gals) each time. If you're using good quality source water, you'll see a big improvement. Another weapon in your arsenal should be aggressive protein skimming...> In thinking along the lines of competition I added a small colony of mushrooms and a small colony of star polyps last week. Mushrooms look great, polyps come out in the morning then close as diatoms bloom. Do I need more light? I was considering 2 or 3 x 96w PC. I intend to stick with soft corals, polyps, and mushrooms. <I agree- get your feet wet, so to speak, with some of the hardier soft corals. You might be like me, and find them more appealing than SPS!> I have a W/D filter, Rio 2500 return pump, DIY skimmer that produces 16+ oz dark liquid per week lately (with virtually no bioload). <Good! Keep cleaning it a couple of times a week or more, if you can. A clean skimmer really works wonders. Another idea might be to yank the bioballs from your filter and rely on the live rock/sand as your biofilter. Bioballs tend to function as a nitrate factory! Wet/Dry filtration is great at reducing ammonia and nitrite, but there's the end product, nitrate- to deal with. Do read about this in the wetwebmedia.com FAQ's> Ammonia=0, Nitrite=0, Nitrate always less than 5. Alk, spg and ph dropped for the low attention month to 5.6dkh, 1.019, and 8.0 respectively. Now at 9.8, 1.023 and 8.6 (day). And Ca=400. The only additives I add to the tank are Seachem Reef advantage calcium for calcium and baking soda for Alk, along with regular water changes. I have experimented with Kalk in the past but not as easy as my two additives added separate days as needed per testing.  These diatoms have been going for 2 months now and covering up my coralline algae preventing further growth. Do I wait to add more corals or does the algae need the competition? <I'd wait until you get a handle on the diatom/nutrient situation.> Any suggestions to my set up/husbandry would be useful. Thank you for all your help, Mike, Orlando, FL         <Mike, just keep doing all of the little things that we reviewed here. Be sure to keep a close eye on your water chemistry, check source water, think nutrient export-that's the name of the game here!  Read the algae control FAQ's on the wetwebmedia.com site. Don't get discouraged! With patience and attention to husbandry, you'll win!   Regards,  Scott F.>  

Diatoms & Iodine Hi So, I don't really need to worry about diatoms killing my corals? <I have never seen or read of a case of diatoms attacking and killing a otherwise healthy coral, but I get the feeling that some aspect of your tank is off due to the brown jelly infection killing your Euphyllias you described previously along with the Moon coral being damaged.> What about the corallines that they also cover? <They could potentially smother them. Unless this tank is under three months old, I would bet you are overfeeding or overdosing iodine.> Recently I went to a pharmaceutical store, I asked for Lugol's Iodine, they told me they don't have it, but they told me that what they have is Povidone Iodine "Betadine" used for wounds and infections. Can Povidone Iodine be used in reef tanks as a supplement too since it is also a form of Iodine? <I am not sure. I would just buy some Lugol's Iodine from a reputable aquarium manufacturer if you cannot find it locally.> Thanks <You are welcome. -Steven Pro>

Brown spots on side of aquarium Hello, I have a 55gal Plexiglas aquarium and have had it up and running for about 3 weeks. I have live rock, live sand, a couple of corals (hammer and frogspawn) along with a couple of clams. My chemical levels are as follows: nitrate=12.5mg, nitrite=0, calcium=450, ammonia=0, ph=8, iodine=.04, carbonate hardness/alkalinity=.36ml, phosphate=.10ppm. I add b-Ionic 1 and 2 about 4 times a week. Any problems with the above readings?  <I think you are overstocked for this age system. I would advise slowing down and letting system age and go through some of the more substantial changes before adding anything else. The algae spots are normal with this level of nitrates and phosphates. Perform a water change to export and lower these. You should be dosing any supplements including B-ionic specifically to water tests and daily usage. I would advise purchasing a good book on the subject, it will save you untold sums of money better spent on enjoying your aquarium. Bob Fenner's "Conscientious Marine Aquarist" is an excellent choice.> My problem is I have noticed within the last few days small brown spots on all sides of my aquarium. I have a Piranha float magnet I use, but even that will not remove the spots, they are that stubborn. The only way I have been able to remove these unsightly spots is with an acrylic safe pad and A LOT of elbow grease. I assume these spots are some sort of brown algae, but do not know for sure. Are these spots normal, and if so, what causes them? Will they go away in time and if so, about how long? I do have about 8 Astrea snails and approximately 15 bumble bee snails in the tank, along with two emerald crabs, two hermit crabs, and a few damsels. Thanks for your help. Steve. <Just the beginning of a life punctuated by days of wet forearms. Keep waste levels low with water changes and let tank age. Take it slow my friend. Craig>

Fast Brown algae Hi There <whassup?> I have just noticed something very strange happen and I'm hoping that someone here has seen this before... I have a brand new 135 gallon FOWLR tank, I have just gone through a fishless cycle (which took 5 days) and added my first fish today (some Chromis). I introduced the fish to their new home and left them, and hour or two later I returned and my tank has turned BROWN...the substrate, rocks, everything is brown.  <a common "diatom" algae bloom. Most tanks get it in the beginning. Do read further on Wet Web Media in the FAQs and archives for more information on it> I'm not sure yet if the brown stuff are diatoms or not, because their seems to be some "hairy" stuff on some of the rocks as well, but its certainly brown.  <the slimy could be a dinoflagellate and if so it is a sign that your tank needs better nutrient control (less food, better skimmer, more carbon, etc)> The glass is not so "infected", but I do see some brown spots on it. The fish look very happy though. <harmless algae> Is there anything in the world that can spread so quickly ? Is it just a coincidence that this happened just after I added my first fish ? Any ideas ? I'm baffled. Thanks Chris <a common problem that will pass in weeks... do read more, learn. Best regards>

Microalgae Gone Now Diatoms Hello sir (whomever you may be today...) :) <Steven Pro in today.> I corresponded with you a couple of months ago when I was starting out on a rather large project with my existing 55 FOWLR. I was fighting a multi-fronted war on microalgae, all coming from my high nitrate problem. I got 2 50lb bags of Southdown to replace my very old crushed coral, and Caulerpa to put in my sump-turned-refugium (lit 24 hours a day). I also bought another powerhead for a bit more water movement. <All good.> The Caulerpa is growing like weeds. Seriously, I can't believe how fast this stuff grows, you can almost watch it. It's the prolifera variety, quite well named! I take out bunches that are bigger than what I originally purchased on a weekly basis to feed to my tangs, and it doesn't look like I've made a dent in the macroalgae density in the refugium. The tangs are very happy with this arrangement, btw. <Do you have to throw some away, too, or do you just recycle it? Recycling some is good, but not really nutrient export since it never leaves the confines of the tank.> Removing and replacing the substrate was a nasty job, but it got done. I also followed your advice on cleaning my skimmer - a Big Mombassa. It is skimming better than it ever has now, I have to empty it and clean it twice a week. <Not bad, but could be a little better.> The microalgae has gone, but guess what? I now have the hugest, ugliest diatom problem I've ever seen. I'm sort of at a loss for what happened here. Why are there suddenly enough silicates for them? The Southdown is supposed to be non-silicate based, correct? <Correct> About the only thing I can come up with is that the microalgae was out-competing the diatoms, and now that they (the microalgae) have been effectively out-competed for nutrients by the MACROalgae, the diatoms have enough of whatever they need to bloom. Sound possible? Likely? <Possible at least part of the problem. The other part being small amounts of contamination from the new sand. Should run out shortly and the diatom bloom, like most, will starve itself out.> Short of getting a Kole, what can I do here? <Perhaps a few more snails, very good diatom feeders.> I've read that RO units aren't actually very effective at silicate removal because after just a short time, the membranes get exhausted and allow silicates through. <Some RO's are better than others. I strongly recommend the use of purified water such as RO, DI, or Kold-Sterile for any marine tank and consider it a must for reefs.> Should I go the chemical route? <No, not cost effective even when they work.> I had to become dependent on chemicals, though (still talking about fishtank here, folks...). Any thoughts / ideas would be very much appreciated. Thanks! ~John <You are welcome. -Steven Pro>

Diatoms Hi- I have a 72 gallon reef tank w 65x4 lighting. I run the blues for 12 hrs and whites for 10 hours each day. I do 5 gallon water changes once a week. Every 4 or 5 days I notice my substrate crushed coral) starts to turn brown until I siphon it during my weekly water change. Is this normal or do I need to cut my lighting hours back a little? I do have stony coral so I am little afraid in cutting back the lighting. The reason I ask is because most tanks I see in photos always look really clean & have very white looking substrate. Thanks for your time! - Ron <Your current lighting seems fine. I have a few other questions/suggestions. Is this a new tank, less than two months? Most newer tanks have diatom problems, which is what that brown you describe is. They usually run their course and die out in a month or two. Do you dose iodine? You may need to cut back. Read through the FAQ on diatoms here http://www.wetwebmedia.com/diatomfaqs.htm -Steven Pro>

Cycling/Diatoms G'day to all, I hope everything is well. my 125 gall FOWLR is in its 14th day of cycling and I am starting to get diatoms covering my LR, base rock and parts of substrate. Is it best to leave these in place or to brush them off the rocks etc. I added about 15 pounds of LR to begin the cycling process, it is nice rock with good coverage of purple coralline algae ,one piece has some sort of coral on it looking thru your site I think it is Goniastrea ramosa but it could be something else). as the tank will be FO should I remove this piece or leave it there-I don't want it to pollute the water too much .will the cycling process and subsequent water changes look after the die off.it was supposed to be cured LR but with this piece of coral am not sure. your advice will be greatly appreciated. keep up the great work. kind regards <Diatoms are completely normal in a new tank. I would let them go. They will run their course and die back over the next month or so. Please read as much as possible on basic husbandry on the WWM site. -Steven Pro>

Is this algae?? DEAR BOB FENNER First let me thank you for having such a great site, with tones of info for the new marine hobbyist, and the struggling marine hobbyist. I have attached some pictures of what seems to be brown algae of some kind, it just appeared about a week ago. I also took a picture at 10 am and one at 2pm today and the growth was amazing. I am new to the hobby and need any advice you have to offer. I have had the 37 gallon tank for four weeks, with two spotted damsels I was told the damsels would mature the water faster). I am using an eclipse hood it has a filter and bio-wheel built in, it has the two florescent bulbs that came with it. the only thing I think it could be is that my tank gets about 20 to 30 minutes of sunlight a day, but since the algae has grown I have closed the blinds. if you could offer any advice on what it is and or what I could do to get ride of it. <Just diatom colonies... can bleach/sterilize the coral skeletons periodically... but I would leave it to succession, growth of other green algae. Please read on WetWebMedia.com re marine algae, control...> any info would be appreciated. and one more quick question, a friend of mine was told that you can mature the water within a few days by sticking a dead fish under the rocks..?!?! is there any truth to this. thank a million -Adam  <A dead fish will also lead the system to cycle... but may be stinky in the meanwhile. Best to take your time here. Bob Fenner> Adam

I forgot to attach the pictures Adam <Ah, some diatom scums... natural... single celled algae... will continue to cover, be supplanted by other types... mainly Greens. Please read over the Marine Algae sections of WetWebMedia.com  Bob Fenner>

Severe Red/Brown diatom algae bloom Hello, I have a salt water tank that is now 3 weeks old. I currently have a *horrendous* outbreak of Red/Brown diatom algae. I put 48 snails into the tank on Saturday, but they can't keep up. It is so bad that I am now noticing some strands floating on the surface of the tank. They get pulled into the overflow box and sucked down into the sump, but still...I am *very* concerned. I have three filters running on the tank: 1) Eheim Pro II 2028 2) E.T.S.S. Super Reef Devil 3) Hagen Powerhead 402 w/Quickfilter attachment filled with carbon. The skimmer is pulling gunk from the tank very well. The water is clear. My water quality parameters are all good, but the algae in intense. It has covered everything in the tank, including the live rock!? The only thing not covered are my 8 damsel fish and 1 Coral Beauty Angel. What can I do? I need some help and/or advise. Sincerely, Mark Schwartz <I hope this is a rather large tank, over 100 gallons. Diatoms are completely normal is a new tank. They will run their course and die out in a month or two. In the meantime, you may wish to cut back on your lighting until they fade away. Also, do you have a lot of surface agitation. The strands on the surface sound as if there is not enough circulation. -Steven Pro>

Brown Algae Mr. Fenner: <Steven Pro today as Bob is busy packing for his trip to Australia and Anthony was mauled by a wild cat.> I have a 90 gal.. FOWLR. Wet/dry filter, canister filter. I coppered the tank. Wrong move. You responded on direction I should take. I removed all of my live rock and crushed coral. I have been filtering the tank to ensure no copper remaining. Then I recently placed 65 lbs. of new live rock with new crushed coral stone in my tank. I currently have two fish residing in tank. I am adding B Ionic solution to assist the live coral. Recommended by live rock supplier. I also had the Kent toxic metal sponge in my wet/dry. Within three days I am noticing brown algae on my glass, live rock (Tonga rock) and overflow wall. What is going on? I recently changed all my filter pads in my wet/dry and canister filter along with new charcoal. Can you help and point in the right direction? Thank you for your assistance on this matter. Regards, Arthur Mendelsohn <The brown algae you see is not an algae but really diatoms and completely normal in new tanks and tanks with a new substrate. It will die out in time, approximately one month. -Steven Pro>

Question about algae Hi Mr. Fenner, <Lorenzo Gonzalez for Bob-in-Asia...> Last time we talked, I was having problems with Cyanobacteria.. Thankfully, I have ridded my tank of the Cyano, but I'm now experiencing a new kind of stuff. I'm getting some brownish/yellowish algae growing on my substrate/liverock/glass very rapidly. The stuff only grows when my lights are on, and when the lights are on it grows fast! However, I've found that it won't grow if I keep my lights off. My situation is similar to a man's FAQ under diatoms. Do you think that is what this is?  <Sounds like it.> What should I do to eliminate this? <Competitive organisms, (Caulerpa being chief) that are easier to control by pruning, are the usually defense. Next is ensuring your water is phosphate free, test it, and switch to purified if your not already using RO or similarly processed supply. regards, Lorenzo> Thank you for your help Kent Krupicka Auburn, AL

Bubble/Brown Diatoms It says ask you a question, so I am! :) <Okay> Our 90G reef is about 18mths old and is generally very happy. It's mostly soft coral with 120lbs of live rock. Filtering has been reduced to the live rock and a plenum based gravel bed (4"+ crushed coral over a 1.5" raised dead space). We run about 1200 gph circulation, generally lighter flow but covering most all corners. All water chemistry is pretty much on the mark. Additives are iodine, MW Black Powder and phytoplankton. Also, calcium, strontium, buffers etc only as needed. <All right> Our lighting consists of 6 NO tubes (2 actinics, 2 Pwr Glow, 2 50/50) and 2 175W 10K German halides. All lighting is well under its age for change out. <Following you> Sorry for the long specs, however most people want to know that before responding.. The question. When the halides are on, we get a ton of tiny bubbles on the gravel and some rocks. It is accompanied by brown algae/slime covering about 1/3+ of the gravel floor. Once the lights shut off (the halides only run 6hrs compared to 12 for the tubes) the bubbles go away and by morning most, if not all of the brown is gone too. Leaving the halides off stops this little cycle, however the corals are much happier with the halides. What causes this brown algae and air bubbles and why does it dissipate so quickly without halides?  <A valid question... life> I am aware of silicates, nitrates etc, but none can be measured and we use RO water. I do have higher levels of waste in back corners and we are doing more to remove it and adding more 'janitors' but the bubbles and the quick growth and collapse in a 24hr period is something I have never seen mentioned elsewhere.. <So called biofilms... with enough primary production with, under them to generate gasses...> Hope you had time to read that! Greg Moore Sauble Beach Ontario Canada <Be chatting. Bob Fenner>

?Diatom Algae Hi Bob, I saw your resume man you have lots of experiences If I have a company I would hire you. <Not so sure... am getting set in my ways as the years tick by...> Anyway my question is where did the irritating brown sort of slimy algae come from, I said that it's slimy because it sort of attached on the Plexi and as the water movement passed it sort of waves back and fort, does the Diatom do this.  <Hmmm, very likely a mix of organisms here, but the majority of the "waving, brown matrix" is Blue Green Algae/Cyanobacteria... Easy to discern with a decent (100 plus magnification) microscope, sample... per the gross traits pointed out on the materials on this group on www.WetWebMedia.com. This stuff originates from... the air, tapwater, live rock, dead rock... these are part of the "winning" decomposers of the planet, that can/do pop-up wherever circumstances allow, favor them... see about this on the WWM site.> I have a 180 galloon, 40 gal sump that I moved from the 100 gal 2 months ago. My lighting is 2 175 MH 4, 4 power compact (actinics) 55 watt each, 2x140 watts VHO, and all brand new bulbs. K2R Ca reactor also new with (aragonite) CaribSea crushed coral media. My water comes from RO/Silicate from Kent. Live sand is 50/100 meaning I got 50 lbs from old tank and 100lbs not a live sand hoping it will be live soon (sugar size from Carib sea). Water quality using Salifert: Ca 498, Alk 15 <These two are too high... cut back on that reactor CO2... you will see an improvement in a week... with Ca nearer 400 ppm, Alk. nearer 10...>, pH. 8.2, Nitrate 0, Phosphate 0, Nitrite 0, Ammonia 0. Could a new lighting system be the source, or some people suggest don't rely on test kits <What? Test the test kits... if they aren't accurate, precise enough, replace them...>, but I change water about 20% but no change in decreasing the algae. I also have macro algae both on the main tank and reverse photoperiod on the sump. On top of this I even added the 150 model of Aqua C running with the triple pass Berlin, just to get rid of this algae. I even placed a UV light.  <Pls read over the BGA sections... your gear, practices sound fine, w/ the exception of the over-driven reactor products... and possibly the addition of more circulation, aeration... do slow down the effluent from the K2, add some powerheads/submersible pumps... and this along with bio-controls will see the end of the pest algae... assured> Some people said it might be the media I'm using, but wouldn't I get some Phosphate value, and this test kit are brand new from FFExpress. I have a friend that came over and said it maybe due to stressing out the system, since I bought 13 new corals, but I told him it even started before I placed those corals. To combat this situation I even placed PolyFilter, and ChemiPure in the water flow, but it has not helped. So I went back to the LFS, they suggested to increase my water flow, but looking at the side view it seems I already have plenty of water movement.  <But maybe still not "enough" dissolved oxygen...> My water return is CAP 5000 rated 1200 GPH, I have a RIO3100 connected into a PVC from left to right, and RIO2500 halfway at an angle, and added another MaxiJet to counter flow the RIO pump. I only have 4 fish and feeds 1/day, along phytoplankton from Kent and presoaked the food with Zoecon from Kent. I have one more guess but, did not take it seriously, because this is considered a new set, but the Live rock and sand has been set up for a year and half, and covered with coralline almost entirely, and I'm sure if it is the case I would get either nitrite or nitrate reading if it is recycling all over. After all of this what else can I do? Thanks, RL <Try the items described... You sound like the archetypal good to great aquarist and I will be here to help you. No worries. Bob Fenner>

Announcing Symbiodinium.listbot.com  Symbiodinium.listbot.com is a discussion forum for researchers interested  in symbiotic dinoflagellates.  The forum was established was established in response to interest expressed at the 9th International Coral Reef Symposium in Bali. A principal objective of this list is to facilitate effective communication between researchers working on the systematics, biogeography, ecology and/or physiology of Symbiodinium and Symbiodinium-like dinoflagellates.  To join, visit http://symbiodinium.listbot.com , enter your email address in the box provided, click "submit" and follow the prompts. If you have any questions or comments about the list, send an email to abaker@wcs.org   Thank you! <To do: post this link on the WWM site for folks interested in endosymbiotic algae>

Algae---diatomsHello Bob,      Help!!!!  I think I have a problem with diatoms.  This is a golden, brownish looking growth starting to grow on my live rock and sand.  I have a 75 gallon reef tank with a wet/dry filter,  metal halide combined with compact fluorescent lighting.  This tank has been set up for around six months without the lighting.  I installed the lights about 10 days ago.  My neglect on the tank was---not only indecisive about the lighting for six months but I didn't do regular water changes either.  My Nitrates are too high.  I looked at the protein skimmer and it wasn't working to well so I have it skimming much-much better now.  If this is by chance a diatom bloom is it detrimental to my tank?  Also, there seem to be some kind of gas bubbles forming on the algae then releasing.  Does this sound like diatoms to you.  I have begun doing 5% to 8% water changes every 3-4 days.  Before I add any kind of phosphate removers or other chemicals I just would like to know the dangers of the algae, and also see if this may run a course then stop.  I am not a believer in dosing with chemicals every time I have a problem, as I believe nature knows more.  Any advice is greatly appreciated.  Stan

<Does indeed sound like an opportunistic diatom bloom... and there's a few ways to approach control, succession. Please read over the articles and FAQs on algae, control... on the WWM site. Bob Fenner>

Question About Brown Spots! (Diatoms) Hello, I am starting a saltwater aquarium. I have had it set up and running for two weeks, I used Fritzyme Turbo Start 900 as the bacteria. The tank is a 46 gallon bow front, and I am using a BakPak 2 Bio-filter/skimmer, and a Fluval 304 filter. I also have a powerhead on, for circulation. I used Aragamax as my substrate.  My question: I see little brown spots on my sand (Aragamax). Today is the first time I noticed them. Is this normal? What could it be? I used a water purified (De-Ion) and Coral Marine Salt. My levels today are PH 8.0, Nitrate 0.1, Nitrate 2.5, Ammonia .25. My specific gravity has been on target. Please help! Thanks! Cory >> Not to worry. Sound like you have a nice set-up and things are going along as to be expected. What you see are colonies of (mainly) Diatom Algae... these will be supplanted with other types of life as time goes by... Do you intend to add live rock to your set-up? This will speed up this succession and lend a great deal of stability to your system overall.... Please do read over the various archives on these issues we have installed on our site: Home Page for much more. Be chatting, Bob Fenner

Dynamite for Diatoms? Bob, its me again. I am using tap water for my 55 FOWLR. I have been getting those diatoms I believe on my glass and some on my rocks. Is there anything I can do to minimize growth? <Create conditions that favor other forms of photosynthetic life... like more light... a sump with lighting and macroalgae... Periodically use chemical filtrants (once a month some activated carbon)... Do your best to utilize clean source water for making up your synthetic, like a reverse osmosis filter...> I know phosphates and silicates are 2 top things that contribute to its growth. I can only use tap water. What are some things that can remove those phosphates and silicates? If I were to buy water, which type should I buy. Distilled, purified? .. . Thanks <Look into an RO for your use (cooking, drinking), and your pet-fish. Bob Fenner, who uses one> I have submitted this question before after looking extensively in the archives and not finding an answer. My prior question shows that it is "closes", so I will ask it again... After setting up a refugium on my sump, and filling it with Caulerpa, I seem to be getting a lot of brown algae in the refugium. The light is on 24/7 (1 50/50 and 1 Full Spec.) I was wondering if I can put snails or something in the refugium to help with this brown algae problem. If not, is there anything I can do to control the brown algae? The Caulerpa seems to be growing just fine. >> The snails would be fine, just a couple at most is all I would use, probably Trochus, Margarita or Astreas as film/diatom/brown algae eaters. With time going by, you will doubtless find various "critters" like copepods, Mysid and caprellid shrimps "just showing up", taking residence in your refugium. Along with succession (the brown/diatom algae being naturally supplanted by other life forms), adding the snails, time going by, the tank will change into what you want. I would not do anything else. Bob Fenner

Brown algae stage I have herd people mention the "brown algae" stage. What is it and what do I do to get rid of it. Its all over my glass, sand and new live rock (from ffexpress). This is a new 75 gal tank with 90 pounds of live rock. I am running a magnum 350 and a Skilter 400 protein skimmer (which has started pulling a lot of scum) My lighting system is 4 56k full spectrum daylight bulbs. My hitchhikers (one peppermint shrimp, some big purple snail and two hermit crabs ) are all doing fine. any suggestions on what I might change or what I need to watch for? Rick >> The "Brown Algae phase?" I like the term... there is a general time in "running in" a new reef tank when diatom scums (this is what the brown stuff is) seem to be proliferating like mad... Most folks use snails (the Turbos are great for this), some types of Hermit Crabs, even Ctenochaetus genus Tangs to biologically help control diatoms... As well as filtering incoming source water to remove silicates (the skeletons of diatom algae are made of this compound)... and going forward, encouraging other forms of photosynthetic life (macro algae, micro forms on live rock through enhanced lighting, elevated biomineral and alkaline content... and many other approaches... Take a look at the Algae pieces and Algae Control I have posted on my site: Home Page for much more. Bob Fenner

Brown algae I have a 55 gallon saltwater tank and I have a problem with brown algae.  I have about 40 lbs of live rock and for the bottom I have all live sand... I have a sea life wet/dry with a protein skimmer and an extra pump for water movement. I have my lights on for about 8 hrs a day. Any thoughts.... Larry from Tampa  >> All sorts... do you know how much nutrient you have in the way of nitrates and phosphates? I'd bet you have tens of ppm from the wet-dry media. Do you have a skimmer, clean the contact chamber and collecting cup every month? This would help. Have any competing nutrient and light-using macro-algae, other photosynthetic life to compete with the diatom/brown stuff? This would help... as would using anaerobic filter media in the sump (like Siporax Beads, Eheim's Ehfi-mech ceramic...), Ever thought of having an alternating light/dark or algae filter in your sump? How about some sand stirrers to keep stirring that substrate? Some diatom eating livestock like Ctenochaetus tangs? Maybe take a few hours to read over these topics in materials posted on the site: Home Page ... If it were me, I'd pull the plastic wet-dry media, and work out a strategy for redirecting the metabolism of your system... Given its present circumstances, algae proliferation is an inevitability. And, we'll be chatting. Bob Fenner

Another question about tank Hi...sorry for my constant question asking. My saltwater tank is turning brown! the top of the crushed gravel has a brown covering, and it is also visible on some parts of my live rock. What is it? also, the sponges on the rock seem to be dying off. Is this because of the brown stuff? Thanks >> >> These events are no doubt linked... the algae you describe are probably diatoms... And their proliferation is due to....??? lack of competitors, abundance of nutrients, lack of filtration/aeration/circulation... can't tell which or all... without more information, testing, knowing the history of your set-up... only you can do this. Get your hands on a couple of general reef/marine reference books and look closely at them AND your system... in the meanwhile, please read over the Set-up, Algae, and Marine Maintenance sections posted on my site: Home Page  Bob Fenner

Brown diat. algae hi bob, Really enjoy you column. I have a 75 gal reef, mixed corals, shrooms  90 #of Fiji live rock tank is 6 mo old chemistry is very good and stable, have  7 colony fish. I experienced a die off of snails as I don't have much algae.  In Jan,00 replaced all of my bulbs (VHO) 2 blue and two 60/40( 110v each). I  have been watching the brown algae start in one area of sand, so I changed 5  gallons of H2O and vacuumed the sand . two days later the brown algae  appeared again. I asked my LFS and they suggested 10 additional astrals(  they advised that they may not work) I waited a few days and the algae is  growing more and more. I shortened by 4 hours the amount of time that my  white lights are on .. I am getting nervous as The algae is appearing on the  rocks. any help you can provide me with would be greatly appreciated. Thanks Ron >> Hmm, am wondering if this brown algae is of diatom, blue green, or some other make-up? If you can, get your hands on a cheapy microscope and take a look at some of this stuff up close... Suspect it IS diatoms (Division Bacillariophyceae)... they have definitive "shells" made up of silicates... and come generally in "groups" (strung together colonies)... anyhow, you'll soon know if you take a look. If they are diatoms, and if one will fit in with your livestock plan, get an Ctenochaetus Tang species (a listing of all, and I'll place images there today, can be found in survey articles, book sections placed on my site: www.wetwebmedia.com... along with some points on selection and care). One of these Bristle Mouth Tangs will gladly scrape the diatoms (I know they're small, but trust me here), up and off the bottom, rocks, glass... in short order... Additionally, of course you could boost photosynthesis to other life forms, denying the diatoms inorganic nutrient, or use chemical filtrants (don't do this) to remove the silicon (silicate, silicon dioxides actually) they need to make their body armor... Or, or... Bob Fenner

Brown Algae on Live Rock Hi Bob, I'm cycling a 46 gal. tank w/ about 65 lbs. of live rock. After testing the water my LFS says I can add a clean up crew in 2 weeks. I have brown algae growing on the live rock right now, should I brush it off or wait till I get my clean up crew? Thanks, Rob O. >> Hmm, it's up to you... For looks, you can clean things up manually... Functionally you can wait... Bob Fenner


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