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FAQs about Marine Macro-Algae Lighting

Related Articles: Marine Algae, Algae Can Be Your FriendRefugiumsAvoiding 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 (Macro) Algae 1, Marine (Macro) Algae 2, Marine (Macro) Algae 3, Marine (Macro) Algae 4, Marine (Macro) Algae 5, Rationale, Identification, Selection/Compatibility/Control, Systems, Nutrition, Disease/Pests/Predators, Culture Algae Use in Refugiums, Coralline Algae: Use in Marine AquariumsMarine 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

Remember: You're lighting all.

cyanobacteria vs. macroalgae lighting      2/27/14
Hi Crew,
Under typical aquarium conditions does cyanobacteria have a competitive advantage over red Gracilaria algae/macro algae in areas of low intensity lighting?
<Define "typical"... under more/less ideal/ized conditions; no>
 I have read on your site that cyanobacteria would have an advantage in low flow areas (I plan on increasing water flow) but I want to know if I should plan on adding more light.  Tank parameters:  temp=78degF; salinity=1.025; carbonate hardness=10dKH; pH=8.15; ammonia= 0.0; NO3=5ppm; PO4= 0.03ppm.
<More involved of course... >
P.S.  Wet Web Media is an extremely valuable site for the home aquarist. 
Anytime someone asks me about starting an aquarium I point them in your direction first.
<Ah yes... twenty years on; the site provides all I had hoped for.
Inspiration, information and outlet for my and others efforts. Bob Fenner>
Re: cyanobacteria vs. macroalgae lighting      2/27/14

Wow!  Fast response.  The ink on my computer screen wasn't even dry before I received your reply.  I will keep perusing Wet Web
<Here: http://www.wetwebmedia.com/bluegralgae.htm
and the linked files above>
 and try to find out what the Gracilaria needs that may be lacking.  My guess is water flow since the shift from macroalgae to cyanobacteria seems to correlate to removing air stones from the system.  I just wanted to know if lighting could be a contributing factor.
Thanks again, Mark  

Re: fighting conch, algal contr., and wet-dry conv. to live sump... Adjusting skimmer, macroalgae light f'   9/11/08 Mr. Fenner, <Chris> When you mentioned water quality mal-influencing skimmer function and needing adjustment to raise the water level in the contact chamber, does this mean: the water quality is poor, or that the skimmer itself needs adjustment? <Perhaps a bit of both; definitely the latter> I tested the water yesterday...salinity 1.024, ph 8.2, nitrate was high (20ppm), ammonia, nitrite, phosphate were all zero. The pump attached to the skimmer has a water flow dial on it...is this what you meant by adjusting to raise water level in contact chamber? <Yes> I read the skimmer manual section pertaining to the water flow dial, and I'm embarrassed to say I'm still confused whether it will push more froth into the cup by increasing the flow (turning knob counterclockwise), or vice versa. <Just try going both directions... Usually opening the valve is turning left/counter-clockwise...> The last question in my previous email pertained to my keeping macroalgae in the display tank...is the existing light (120W total) sufficient to keep the macroalgae happy in the display tank (72L X 18W X 22H) with 100 lbs or so live rock, and 1-2 inch deep live sand substrate? <Mmm, likely so... there is a huge span of "useful" to optimal quality and quantity of light per species, Division of algae... with much photo-adaptation> They're on a timer, approximately 8 hrs per day. This was my first large marine tank, so I contracted with a local aquarium maintenance company to plan and install the system (equipment, lighting, hard plumbing, etc.), hoping to watch the owner work and ask enough questions so that I'd be more comfortable on my own for future systems. <Good practice> At the time, I saw a Berlin skimmer online review that was consistent with your comment (that it wasn't the best choice), but I relied on this person's expertise, since he said he had personal experience with this brand skimmer. It was also his opinion that since this was not going to be a reef tank, 2 standard fluorescent fixtures (housing two 50/50 bulbs each) was all I needed. <Mmm, short-sighted in my opinion... I urge folks to aim at likely upgrade scenarios... in the hope, knowledge that they may well "graduate" to other types of systems in time> Thanks, Chris S. <Welcome. Bob Fenner>

Macro algae lighting: ?'s  9/28/06 Is 130w of 50/50 (10k:Actinic) power compact on a standard 55 gal enough to keep it thriving? <For? What sorts of organisms, purposes?>    What would be the best choice to go in a display 55? Grape Caulerpa; Chaeto I want to grow some macros to naturally knock the nitrates and phosphates down in my tank, to next to nil I just cant seem to drop to lower than 5-15ppm ever, it's a FOWLR with hope of anemones and a few leathers maybe...any suggestions, <Chaetomorpha over the Caulerpaceans... a refugium... anemone, not anemones> My setup is a 55gal standard Fluval 404 fully loaded with 1 Purigen, and 2 ½ cups carbon etc (bio-media) , a marine land 200 with carbon only, 260w compact fluor fixture, but only 130w 50/50 on right now, 70 lbs beautifully aging LR  and about 4 inches LS assorted critters 1 sand sifter, 16 hermits & 3 emerald crabs, 8 Nassarius snails,  5 baby small asst damsels 2 maroon yellow stripe clowns and a lawn mower blenny,  I want to advance this aquarium to a reef, but cant get my nitrates to drop, <The canister, more... Please read here: http://www.wetwebmedia.com/nitratesmar.htm and the linked files above> had a skimmer (Berlin Air lift 60) for a while with no drop in the nitrates so I took it off after 3 mos.  What macro would be the best choice?   <And here: http://www.wetwebmedia.com/maralgae.htm and the...> I just don't have the $$$ for a refugium or sump at the moment... <Save up, trade/sell the canister filter, DIY... Please read: http://www.wetwebmedia.com/marsetupindex2.htm....> HELP!!!??? BTW BOB CMA is an awesome book!!!  The most enjoyable thing is aquascaping by far thanks A LOT Crew only reason I am still in this wonderful hobby!      <Patience, planning... reading... thought, then action. Bob Fenner>    

Re: Macro algae lighting: ?'s  9/29/06 So the prob is my canister filter? <... if/when you read you'll see that this, these are contributors...> What grow light would be the best for a refugium with Chaeto in it? Wavelength and what not, I want it to just grow out of control, that would entail the most nutrient export right?...I have read my self in circle on WWM about this subject just cant make a firm decision.  Thanks again appreciate the help < http://www.wetwebmedia.com/refugltgfaqs.htm Don't write... read. RMF>

Lighting macroalgae Hi crew!! My revamped 90 gallon is up and running.  I bought a few SPS corals(Bali Acropora, Montipora, birds nest) tonight, and they are doing very  well.  My local store( RI- Rumford Aquarium, an excellent, clean,  informative store) gave me bunches of Green Grape and Feather Caulerpa with my  purchase.   <Great to hear of "good" stores> I have a 32-gallon rubbish barrel re- circulating water to my tank( for added water volume). I would like to have this barrel house the above mentioned algae to absorb nitrates and such.  What is the best lighting, in watts, bulb type, and Kelvin, to make these thrive? <Mmm, tough to say w/o dimensions provided... but something that you can afford to run continuously to drive photosynthesis (Caulerpa can... and some folks, me included, believe should be illuminated continuously to discount the likelihood of it "going sexual"... Do read re. Probably a small compact fluorescent unit> My re-done reef is doing very well, and it is in large part due to the information that you have given directly and off your website.  Thank you  for both!!! James Providence, RI <Bob Fenner, born in Northkingston, both parents in Providence> Re: Unidentified Green "Grass" Macroalgae, lighting 8/14/05 Hello, <Hi again> Thanks for the help identifying the Chlorodesmis and the link to the page about the other green macroalgae.  It was very informative.  BTW, do you think that it is advisable to run the light (32 w PC) in the refugium 24 hours a day on the Chlorodesmis or would it benefit from a "dark period?"  Many thanks! Best, Christopher <Almost all other life other than Caulerpa spp. should be afforded a "dark period"... I would run the light during all the hours when your main systems lighting is off, overlapping a few hours with the sump/refugium. Bob Fenner>

Old lights, i's 11/3/05 Hello I am setting up a new marine tank (48"x24"x24") and i will be taking one light off my old tank (a 40 watt marine-Glo) to use on the new tank whilst the live rock cures. Once that has occurred i will add the other light from my old tank (a 40 watt power-Glo) as well as the livestock (2 percula clowns, 1 hawkfish, 1 banded shrimp, 1 coral (id unknown)) These animals are all traveling well. Will the 40 watt lighting be sufficient to promote macro algae growth on the live rock? <Mmm, no> If not, will both lights be enough? <Two normal output fluorescents of 40 watts? No> Do i need an upgraded lighting system? <Likely so> By the way, I'm bemused at why tangs are so popular to cut down the algae. I HATE tangs! but i LOVE the macro algae. I learnt from a past experience never to get another tang after my previous one nonchalantly munched away all of my prize macro algae and wouldn't touch the hair algae. Thanks for your help! <Please read here: http://www.wetwebmedia.com/maralgae.htm and the linked files above. Bob Fenner> 

Light for coralline and macro! <Helllloooo!> I have a 55 gallon saltwater aquarium with fish and live rock. I have not had very good coralline algae growth and I have a small amount of Caulerpa that is growing very slowly.   I have a twin set-up with fluorescent bulbs; one is regular daytime and the other is actinic.  I change my bulbs every six months; I recently put in a 10,000 K and an actinic from a friend who had a previous setup. I do not know how long he ran them for. <That may defeat the purpose of changing the lamps, the idea is to have fresh lamps every 6-10 months.> I know I need more lighting in my tank and I would like to up grade my tank lighting and get either VHO or metal halide. <Actually, you may find that this is the best lighting for coralline algae, my rocks are WHITE under 400w MH.> I am still planning on keeping the twin fluorescent bulbs in my set up and I would build a canopy for them all.  I am looking in to replacing the fluorescent bulbs with  the Coralife High Intensity 20,000 K and the 10,000 K. <Nothing about the intensity will change by simply switching out the lamps. Increasing the intensity would only happen with a complete fixture change.> Do I need to up grade, if I do what would be my  best option with my setup? <I think you're fine. If you want some coral, then yes, you'll need to upgrade. Enjoy! -Kevin> Thanks, Codie

Lighting over Chaetomorpha 7/21/03 Dear Anthony, <cheers, Howard> After reading Reef Invertebrates, I feel that I should replace the refugium lighting. <Okey-dokey> What is the ideal lighting system over a 30 gallon refugium with the purpose of cultivating Chaetomorpha along with copepods and amphipods?   <a single 100 or 150 watt double ended HQI lamp (say 10K) would rank very high in my book. Do use a parabolic reflector if possible. Seek 4-5 watts per gallon here at any rate> There are so incredibly many options, I would appreciate your personal opinion regarding spectrum, watts, and cycle of the appropriate pendulum metal halide light including your favorite brand. German? <for MH in general... I like Iwasakis, Aqualines and Ushios. Not inclined to take most others for free <G>. Radiums are also very good... but the 20Ks are scary blue (too much so for shallow water Algaes and some corals). and 8-12 hour photoperiod will be fine> Many thanks, Howard in Wisconsin <best regards, Anthony>

Refugium lighting One quick follow up to the 13 watts PC-  Am I correct in saying it will be sufficient to grow Chaetomorpha & Gracilaria a refugium of these dimensions? Or do I need to step the light up like 27 watts? Gracilaria <these macros (like most) are shallow water species and require as much light (watts/gal) as full reef displays. You should aspire to provide at least 5 watts per gallon in this case to keep them successfully. Anthony>

Vitamins and Lighting for Gracilaria and Ulva 1/5/03 Hi, Sorry for filling your inbox - we have an additional question(s): <No Worries!  Adam Here tonight.> We purchased Gracilaria Parvispora and Ulva algae for our yellow tang (and hippo tang if you recommend one).  I think we will have to grow it in a separate tank (our sump is an ecosystem and the 18 watt pc lighting stays on 24/7 - may be too strong). <Probably not too strong, but maybe an inappropriate photoperiod.  Also, if you are growing Caulerpa, it would probably out compete the others for space, nutrients, etc.> - Would you recommend adding vitamins to the water to enhance the Algaes' food value we'll be using the old tank water as we replace weekly)?  If so, would that be vita-Chem, Selcon, garlic... all... or something else?:-) <Probably just a bit of iron.  Everything else should come from the tank water.  You may wish to add the things you listed to a single portion just prior to feeding, though.> -  How much light would you recommend and which type to best grow the Algaes?  We've seen some recommendations for actinic and some say florescent is fine. <A couple of generic fluorescents should be fine.  No special spectrum necessary.> Thanks once again in advance!!! <Glad to!  Adam> - Doug

Refugium (macroalgae) Lighting This question is directed at Bob Fenner (unless someone else would like to answer)...when you spoke November 21, 2003 at the Sacramento MARS meeting you included some information regarding macroalgae.  Maybe I misunderstood you, but did you say that Caulerpa was the only macro that could be lit 24x7? <Yes, did mention. As far as I know the Caulerpaceans are the only continuous photosynthetically active macroalgae> I mentioned this to a friend of mine that has Ulva & Gracilaria lit 24x7 in a refugium.  I looked through the information in your new book and it did mention that Caulerpa could be lit 24x7, but there wasn't anything saying that the others couldn't be lit 24x7.  Can you please elaborate why Ulva and  Gracilaria shouldn't be lit 24x7. <I would separate the area where the algae are into two compartments and only illuminate either side 12 hours a day>   I know you mentioned it during your presentation, but I think our table was on the 3rd pitcher by the time you did so. <Hee hee! Most photosynthates require or at least do best with a "dark phase" period... and so would grant these other algae such... either by turning their light off some hours during the "day" of the main tank... OR dividing and lighting only part daily. Bob Fenner> Thanks Marc Daniels

Lighting Chaetomorpha (1/22/04)    Hi, and thank you for your good work !! <A pleasure>    I'm searching for a couple of days on the web what is the amount of light (in lumens) the Chaetomorpha algae do need and how many hours/days at most can we light it?  <Don't know how many lumens. Standard output or PC fluorescent lights should be fine. I light mine with 46W of PC. W would not recommend more than 12 hours per day.> Is it the best choice of algae to put in a refugium with a deep sand bed  and to do nutrient export ?! <A matter of opinion. There are pros/cons to all algae. Read the FAQs on Chaeto & Caulerpa and choose which is best for you.> Thank you ! Steve Timmons  <Hope this helps. Steve Allen>   

Dwarf Seahorses, Refugiums and Macro Algae 5/2/04 Hey gang! Good morning from New Jersey! <Good afternoon from the other side of the country> First off, I'd like to thank you for the wonderful service you do for us fish geeks. It is greatly appreciated. < You're most welcome from  another fish geek!> Now, I wanted to run this past you guys before I end up bashing my head against the wall later. <Yikes......Please refrain from head bashing. Then the seahorses will really have a problem and you will have a headache.> I currently have several dwarf seahorses in a five gallon but the brine shrimp is really taking its toll on the nitrate levels. <Hmmmm I assume you are feeding live.  My first thought is perhaps you are over feeding a bit. You might want to cut back a bit and do more frequent water changes. If you are not keeping any clean up critters you might want to consider a few Nassarius snails, which will quickly consume detritus, uneaten food, decaying organics, and fish waste. In addition  a few of the Hawaiian red shrimp Halocaridina rubra would feed on excess brine shrimp> So I plan on upgrading to a 10 gallon for increased water volume. I would like to partition off half of the tank for a refugium.  The side that the seahorses are on would be bare bottom for easy cleaning and the fuge side would contain a DSB with some rock and macroalgae. The hang on filter would uptake from the seahorse side, spill out through the fuge and flow back into the display area. <It's not the typical dwarf set up but sounds very good actually. I have a friend who kept her dwarfs very successfully in the 40g refugium connected to her 125g reef.  Be sure to provide some sort of barrier to the intake to protect them from getting sucked against the intake......perhaps a sponge. I would probably be tempted to go with at least a little bit of sand and some of the macros on their on their side for a more natural environment. Unless of course you are keeping captive bred dwarfs which might be used to a more barren tank with a glass bottom. I have one concern .......live rock and the macros combined with live Artemia is the perfect breeding ground for hydroids which as you probably know can wipe out an entire tank of dwarfs. You can avoid this by treating the rock and macro algae with Panacur for 3 days There is more information on dwarf seahorses and their care on www.syngnathid.org  in the Tiny Tots forum and specifically hydroids and this treatment regimen in this thread..... http://www.syngnathid.org/ubbthreads/showflat.php?Cat=&Board=Dwarfs&Number=11739&page=&view=&sb=5&o=&fpart=all&vc=1 > So my question is concerning the macro.  I have access to several types but I'm not sure which would be best for this application and I know that mixing too many species, especially in this size tank isn't good.  Keep in mind that dwarves fair best in 1.019 - 1.021 SG. <Yes I am familiar with that.> I have access to the following: feathery Caulerpa , grape Caulerpa (...would prefer however not to use these), Halimeda ,Penicillus ,Udotea ,Ulva, red Gracilaria, green Gracilaria, and Bryopsis (haha! want some?) < I think I will pass on the Bryopsis but thanks so much for the generous offer <G> anyway . You are limited here by the optimal specific gravity range of the Dwarfs, with the exception of the Penicillus which can be kept at 1.020. The rest of these species have an optimal specific gravity range of 1.023 to 1.025.> Depending on which macroalgae you think is best, do you think I could get away with a 15watt NO 9325 Kelvin bulb on a 10 gal? (I'm thinking probably not!    hehe) How about 2x13 watt PCs 50/50?..or would you suggest a different Kelvin since the only thing in the tank that would benefit from a specific spectrum would be the algae? <You can find the answers to this in this article Macro-Algae Use in Marine Aquariums http://www.wetwebmedia.com/maralgae.htm . > thanks, chickie moomoo <You're most welcome, Leslie>

- Lighting for a Saltwater Planted Tank - Hi. <Greetings, JasonC here.> I just purchased a Saltwater setup with the intention of keeping larger fish such as a clown trigger (possibly), a snowflake eel, maybe a harlequin tusk but all of this of course would depend on if they can be kept in a planted saltwater aquarium. The setup is as follows:   200 gallon tank 30 gallon sump 3 250 w MH lighting 2 4ft Blue actinic bulbs 2 fans for the MH lighting plumbing for the sump 2 built in overflows (1 in each back corner of the tank) A custom built stand and canopy With the above lighting setup will it be possible to have a beautifully macro algae stocked tank (with the addition of a good skimmer which I hope that you can recommend both size and brand) with some live rock and some fish. <I'm a fan of AquaC skimmers.>  I have been told this is too much lighting but I have read about peoples tank setups and have found a few with this much lighting and planted macro-Algaes. <Well... in my own experience, most people who have macro Algaes in their tank use them as an adjunct to the system and not as the major feature, but no matter. Either way, the lighting you have will be more than adequate to grow very robust quantities of macro Algaes; probably to the extent that you will need to remove large quantities on a semi-daily basis. Do be cautious though... if algae becomes your major feature, you may find your fish oxygen starved when the lights are off and the Algaes begin to respire.> They are beautiful but I cannot get them to respond to my posts of questions.  Can you help me? <You seem well on your way.> Thanks Robin <Cheers, J -- >

Refugium Lighting And Macroalgae Use Hey Guys, <Hello! Scott F. with you today!> A couple of questions. I have read a lot of the FAQs pages but I have yet to see a definitive answer. Do you think 24/7 or a reverse cycle lighting is better. <Well, I personally favor the 24/7 lighting in the sump; it's just plain easier to do, and it has worked well for me (I am of the school that says, "If it isn't broken- don't fix it!"). However, it is certainly not "natural", and people have theorized that the constant light keeps the macroalgae in a sort of "stasis"- much more definitive research has to be done in this area. The "reverse daylight" technique has worked well for many hobbyists. The primary function of RDP and 24/7 is to maintain a more stable pH in the display tank. It really is open to debate and experimentation as to which is better> Also I am using a combo of grape, prolifera, and feather Caulerpa. My Nitrites are 0 my phosphates are 0 also. I see that you do not recommend Caulerpa why? <Caulerpa tends to be an extremely invasive macroalgae, even in a refugium situation. Also, it has a propensity to "go sexual", at which time gametes and cellular material are released into the water as part of the algae's reproductive cycle. This can cause a depletion in the tank's oxygen levels, and a substantial degradation of water quality as these materials decompose. Also, studies by hobbyists seem to have implicated that Caulerpa produces substances which may inhibit the growth of corals in closed aquarium systems. Some of these substances can be leached when the runners are broken, as they may be during "harvesting" of the algae> If you had one Caulerpa to choose which would you use or is a combo good. <If you are determined to use Caulerpa, I'd use a single species. I have always favored C. prolifera, myself. Frankly- I'd recommend an equally hardy, productive, and useful macroalgae, Chaetomorpha linum, which has many of the "benefits" and none of the downsides of Caulerpa. I use this macroalgae exclusively, and am very satisfied with its results> My refugium has only been active for 2 months but so far so good. Should I expect any problems in the future? <If your refugium is well thought-out, and a compatible combination of creatures inhabits it- there should be no difficulties> Also lots of amphipods in refugium, how can I get this life in tank? Fish eat all in seconds before they can hide. <You could simply net collect the "pods and feed them that way. Or- simply allow some to be carried into the tank via the refugium return...Maybe not the most efficient way- but it works> If you were to 86 Caulerpa what would you use (mangrove?) what are your thoughts? <Chaetomorpha, as outlined above, or possibly Gracilaria> By the way I am using a protein skimmer. Thanks Jim <Well, Jim- lots of controversy here. Make your choices based on your needs and concerns...Hope this helped. Good luck! Regards, Scott F>

Keeping sand bed clean cont. Hey Bob, Just wanted to tell you that I did get a sand bed activator kit from IPSF about 3 days ago. So far its been working pretty nicely and hopefully I have my hair algae under control now. I just had a quick question for you. I got the Tang heaven red, green, and yellow in my kit and I have it sitting in an eclipse 6 gallon tank in my stand. I added a small amount of fluid from my skimmer up about to weeks ago and hope to keep the nitrates high so I can grow this stuff for food (and maybe for some decoration and nitrate processing later). My question is about how long I should keep my lights on? Since its in my aquarium cabinet I have been keeping them on 24 hours a day but am not sure if they should have a dark period. What do you think? Thank You, Jonathan Pac <Some dark reaction time is likely a good idea here... maybe four to six regular hours per day. Bob Fenner>

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