Terrible Advice Tuesdays (T.A.Tues): No Coraline? Clearly Something Is Wrong

Terrible Advice Tuesdays (T.A.Tues): If your saltwater tank doesn’t have coraline algae growing in it, then your tank isn’t healthy.

The rest of the story: The hunt for coraline algae always makes me laugh as there are hobbyists who hate it and want it out of their tanks (*cough* Joe). Everyone else likes coraline algae and wants it to grow in their tank as soon as the tank gets wet.

The thing to keep in mind is that if coraline algae isn’t growing in your tank, that doesn’t tell you anything about your tank’s health. I’ve seen countless saltwater tanks all with perfect water parameters and there isn’t any coraline algae in the tank. I’ve also seen tanks that look like toxic waste dumps and coraline algae is happily growing all over the tank.

If you don’t have coraline algae in your tank, getting it grow could be as easy as making sure your magnesium (Mg) and calcium (Ca) levels are in check. Or your tank might not be the coraline algae type for some unknown reason.

Whatever you do, don’t freak out because coraline algae isn’t growing in your tank and certainly don’t reach for a bottle that claims to boost coraline algae growth.



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Comments for this article (57)

  • JasPR says:

    Right on brother!
    ” if you build it, they will come” is never so true as when you are talking about a closed environment once water and ‘life’ has been added. The subsequent ‘evolution’ that then takes place is ALL about what the unique parameters, conditions and nutrient sources are. And those are not identical from one aquarium household to the other.
    1) pH, mineral content, buffering system
    2) temperature and photo periods
    3) feeding techniques/ nutrient sources and amounts
    4) turn over rates
    5) level of nitrification activity
    6) maintenance routines/ water change schedules
    7) nature of well water or tap water
    8) stocking levels
    9) species and micro species introduction ( or lack thereof) hitchhikes and regional variations

    No wonder all are tanks look somewhat alike as they progress thru time and maturation stages, yet groups of ‘unique’ issues show up with varying regularity amongst different hobbyist systems.

  • Matt says:

    If someone would like to trade me the hours of my life I’ve spent scraping the stuff off they’re quite welcome to have mine!!!

    Especially now that I’ve dropped my flipper and bent the scraper! 🙁

  • RICH says:

    WOW !!

  • JasPR says:

    Amen brother Rich! Amen! 🙂 JasPR

    Rule # 3 – Nature abhors a vacuum !

  • Merne says:

    This is a good post, Mark! I was one of those “When does the coralline start growing?!” types when I first started. I even bought coralline spores (lol). Now I have urchins that eat it.

  • kevin says:

    Imho coraline algae is one of the tings that make a tank look more natural.

    I’m quite lucky i don’t have any outside my display. I’ve seen people clean simmers sumps etc etc with full with Coraline. But for some reason it will only grow in my display tank.

    One of the other things you read a lot is that you shouldn’t keep sps corals until you see the coraline grow quite fast. It might be a good time to start. But keeping parameters stable by measuring is a better way to go then look at Coraline algae.

  • Merne…I got a request once to overnight ship coraline algae scrapings to Hong Kong!

  • Matt…what do you have against coraline algae?

  • Tony says:

    I have it growing in my tank, in my Refugium I have green and pink/red coralline algae. If you keep up with it you can control it. It grows like crazy on the back glass I don’t touch it. Side and front I keep clean. My tank is mostly fish olny. Just a hand full of non fish things 1 rose bubble tip, 1 Hammer coral, 7 mushroom corals 7 fish over 100lbs of rock tank 75 gallons. DIY Refugium 14 gallons of saltwater +/- all good so far and 2.5 years in to this set up. All I say is PM is the key.

  • kevin…don’t keep SPS till coraline grows?! First time I’ve heard that! I may have to use that for another Terrible Advice Tuesdays post!!

  • Tony says:

    I say the same! look natural!

  • Nik says:

    I am one of those who don’t care for coralline algae either. Luckily I don’t have a single trace of it in my tank

  • Bradley R says:

    I don’t have a problem with it growing in my tank. As long as it stays off the front glass I’m OK, but for real what’s the problem you people have with it? LOL

  • Stevie V says:

    To me, it stands to reason that if I let it grow on the back wall of my tank, that it will help harbor life thus helping stabilize the system a smidge more. Besides it looks authentic.

  • Kathy says:

    My black long spine urchin eats it all!

  • sanchezkk says:

    I love the way it looks. I have it all over my back wall. I sometimes have to scrape it off the side with a credit card like tool so I don’t scratch the glass. My friends come over and we have a scraping party. After the party is over they leave with coralline algae in disposable cups so they can treat their tanks with purple, red, green, yellow and white coralline. IMHO, it’s a great look.

  • easy E says:

    I hate coraline, it is a huge PITA for cleaning and im personally not a huge fan of the colour, i prefer natural live rock colour for some reason.

  • Cyrus says:

    It’s amazing how far we have come in such a short span. The ancient reefers ( you know, from the 70’s on) will recall a treating the rocks with a touch of bleach to “keep them clean”. I’m just glad we have guys like Mark who put some logic on the table. Side note, my most hated comment, “that’s how we’ve always done it”.

  • Cyrus…I remember taking all my rock out (it was nothing more than coral and barnacle skeletons) and bleaching it once a month. Back then you were judged on how white your rocks were of all things!

  • sanchezkk says:

    Wow, bleach? And to think we stay away from chlorine type chemicals now these days.

  • dave says:

    this is a funny subject., my orig tank I could only get green coralline to grow in my tank, last x-mass it cracked so I bought another tank. now 7 mo’s later I don’t need a back drop its totally covered in red coralline, and I do mean COVERED!!!the thing that did it for me was to go with b-ionic and now it is everywhere!

  • Beth says:

    How white the rocks were? OM Gosh! I would have quit a long time ago.

  • Matt says:

    Mark – Nothing … but when you can see in from three sides of the tank you spend a while with the scraper each week… 😉

  • Nik says:

    I also remember the bleaching days, and before that no rock, just some dead corals for decoration. Myself, I am a pariah in salt, I don’t care much for coraline algae heck I don’t even like corals. Give me some beautiful fish, and a tank on auto pilot and I am happy.

  • Chris says:

    I have florescent orange spots on my coraline. It comes and goes but recently I have seen bigger spots. What the heck is it?

  • Cadmanof50s says:

    Just had to add to Nik’s comment. I too remember the days when the rule was to soak all the beautiful, white coral in chlorine bleach to kill every last living organism. Only to have it turn green again in two weeks. The nitrate cycle would take as long as 3 months to start and end because we had no concept of live rock. Just those wonderful under gravel filters! We’ve come a long way.

  • Mr. Microscope says:

    I see that orange stuff too sometimes. Looks awesome under blue LED’s. My favorite is the teal coralline. I have a little here and there and it’s really slow to grow. I’ve never seen it in another tank though.

  • Beetle Bailey says:

    Whoa! you really hit a nerve with this one Mark,personaly I love the look of coraline ,as so many others have said it looks so natural and make my enclosed system look so much more alive ,and if it becomes a problem pop in a small urchin,research which ones,but they will happily chew up your coraline algea as I have done in the past

  • Nik says:

    ANG the memories, under gravel filters, protien skimmer made from an oil funnel and pvc pipe with the air stone, salt creep destroying everything, T12 shop lights with grow light bulbs….those were the days, if you had a salty back then you had accomplished something. New people have no idea how good they have it.

  • sanchezkk says:

    I have to agree with Mr. Microscope, the orange does look great under the blue LEDs. But teal, I have yet to see.

  • Beetle Bailey says:

    p.s Amen to Cadmanof50s ,the good ol days ,I remember my first ehiem canister filter with ceramic pipes ,that was out there technology and coraline in your tank back the , bah humbug who ever heard of such things, out rageous!

  • Nik says:

    I was high end cause I had a skimmer, and i used the carbon canisters on the under gravel outputs.

  • Anyone remember the little carbon catridges you would put on the outputs of your undergravel filter? I wonder how long those were really effective!

  • Anyone remember the little carbon catridges you would put on the outputs of your undergravel filter? I wonder how long those were really effective!

  • Joe O. says:

    Hey Mark! I don’t haye coraline algae and want it out of my tank! I love the look of it! Lol.

  • Joe O. says:

    Hey Mark! I don’t hate coraline algae and want it out of my tank! I love the look of it! Lol.

  • Arthur says:

    I wouldn’t have a tank without the coraline! I have an aquarium so I can have a piece of the marine world in my home. I live a long ways from the ocean, so I want my own piece of it. No coriline is like wearing those jogging pants that look like JEANS, you just don’t want to do it.lol

  • Barbara says:

    I love the look of coraline algae but with my tank being a room divider I don’t have a back of tank for it to grow on. At this point it has never grown in my tank so I dont have to scrape off something beautiful.

  • corocora says:

    For some reason in my tank only the rocks attract coraline algae. Tiny specs
    show up on the glass occasionally which I quickly remove so I can stay ahead of it. The back gets algae film which the CUC take care of, but no coraline. My first tank was a constant challenge to keep large blotches off the glass while the back was totally purple. That tank was acrylic, my current one is glass. Could there be a difference in coraline tendency?

  • Nik says:

    Coralline algae loves plastic, it does not do well on glass.

  • BuilderofDreams says:

    Personally i think it belongs on my rocks and no where else.
    Once a month i blade my glass box front-sides and the back.
    Pumps are cleaned imediately at the first signs of it.

  • corocora says:

    Thanks for clearing that up Nik, and correcting the spelling of Coralline.
    And I agree with you, BoD! Where in the ocean can one find a glass box with red calcareous algae growing on it and its power heads?

  • John says:

    Carbon cartridges and little air stones for flow and turn over ! o my lol !

  • Cadmanof50s says:

    …and of course… the more micro bubbles you had the better!!! Better aeration right? The walls behind my tank are still permanently salt encrusted from years of spray. Now lets really put time into perspective. Who remembers the little corner filters that used charcoal and filter floss and air pump to drive it! That was my first tank setup…and yes… it was before the first moon landing!

  • Chris says:

    Mark, I’ve seen you make more than one post about not using coralline algae boosters. What are the down falls to such products?

  • thurman says:

    well i started a new tank last year and all my pearameaters look good but no corline in the tank at all !
    i need some good scrapings to get the tank seaded now with it .
    i started with dry rock and dry sand and its been a long go !
    and have added a lot of the tank over the last year pods and rotterferds and fish very very slowley to the tank.
    aka my back room wich was a screanded in porch now if finshed off and looks like a dyi nightmear ! but i am trying !
    if someone can send me a oz of coraline chips i would be gratefull for it !
    get hold of me at rocking_b_m_e_ranch@ yahoo . com
    thank you so much

  • Dan says:

    Hey Mark,

    How do you recommend quarantining new corals? Ive read your book on fish quarantine and was hoping you could highlight the differences with corals (ie lights, dips, etc) to prevent nuisance stuff getting in a tank. Thanks so much!

  • Nik says:

    ahh yes the wall of bubbles. as for the cornere air filters, I am ashamed to admit I still have 2 or 3 in the box of fish stuff.

  • Nik says:

    ahh yes the wall of bubbles. as for the corner air filters, I am ashamed to admit I still have 2 or 3 in the box of fish stuff.

  • Nik…wall of bubbles! I forgot about those! I had the bubble disk too. I remember having to soak it for an hour before I could run air through it.

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