How to promote Coralline Growth

I have read that rock covered in coraline is a less effective bio-filter than rock without coraline. This certainly makes sense because the coraline basically seals the rock's pores reducing water flow into the surface.

Does anyone know of any testing that proves or disproves this theory? What do other reefers think of this idea?
I have no doubt that this is true. Another reason to use LS as your primary bio-filtration.
Great succinct article Greg.

I like that you included a list of coralline predators, you can add those little starfish (forget species but they are in hitchikers archive). I have watched several graze an area of coralline, leaving behind pale areas (slightly faster than watching grass grow).

I also have had a recent growth explosion of halimeda calcareous green macro algae. I am convinced that this rapidly depressed the calcium in solution and thus affected coralline growth.

I too am now using the Kent buffer and seachem calcium in an attempt to get things back to correct levels.

Some have suggested that coralline grows better with more actinic light. Any thoughts on this other than different species hypothesis?

I read that brighter light stimulates the growth of the brighter and lighter shades of coraline and lower light levels/colors stimulate the darker coraline.

I suppose actinic light also brings out the contrast of the coraline making it easier to see. I notice that I get more pink under the MH but grow purple coraline in shadows.
good artical gregt, One thing a lot of people dont know about calcium is that in order to keep or raise your calcium to the 400-450 level you have to maintain your stronium level. It is a complicated formala, but in lay terms you need to have your stronium at the proper level or your calcium will not raise or maintain. This is probibly why you had sucess when you did water change (you were adding stronium as well as other trace elements). If you dose with a stronium additive bring up the level you will have sucess with raising and maintaining your calcium.

It is true that different light levels will produce different types of calcerious algea. your purple corraline perfers lees light but it will still grow under intence light, just not as fast

From what I have read the rock Portion of Live rock does not play a big part in filtration, but the animals (micro algae, corraline algae, calcerious tube worms, fauna, ect) provide the filtration that we all desire.

I forgot about those dreaded starfish! My choc. chip should have definitely made it into the article. Thanks for the reminder.


I've heard the "other trace element" concept, but it was magnesium, rather than strontium. Hmmm...


You can add certain types, if not most, of urchins as coraline predators.

Greg - I would have to agree, I have heard and read the same about magnesium and I dose regularly as well. This is the first I've heard that about strontium. I have been told strotium does promote coraline algae growth though.
I have an Atlantic Blue Tang - and I have to tell you, this guy grazes on pink coralline algae like it was his last meal, then he killed all the caulerpa as well...
I have low light and coralline growing really well.

I have also seen coralline algae covered rocks around 60 fsw in 45 degree water up here. There's not a lot of light down there, however the sea urchins was found slightly deeper in 65 fsw and on sand bottom, not on coralline covered rock as one might expect - I was not doing scientific observations on that dive but I'll take a better look next time I got there - or if I see it in other places.

hey guys,
i agree with you in that maintaining ALK and maybe pH are important factors. of course you need Ca, but you dont really need it at 400 or above for coraline. my reef has been set up in its current home for about a year now. coraline never really took off, or grew for that matter. as of late i have been more diligent in monitoring my water and i have been using superbuffer and turbo calcium. along with kalk. man o man the coraline has taken off like there's no tommorrow! i just wish more of it would grow on the rocks and not all over the freakin glass ;p
I guarantee that strontium will cause the coralline algae to explode. Find a source for Strontium Chloride and mix up a 10% solution. For a 100 gallon tank add;

day 1 24.2 mL
day 2 24.2 mL
day 3 24.2 mL
day 4 24.2 mL
each week 3.9 mL

Within 1 week, you will see more coralline growth than ever before. I was getting really good growth when I was dosing the strontium with iodine and kalkwasser. I switched to the Restore product and the growth stopped. Last week I decided to add some more strontium and it took off again.

There may be several other ways to get the stuff to grow, but this is the easiest I have ever seen.
My tank is FULL of coralline and I have never dosed Strontium. The only thing that I dose my tank is B-Ionic and sometime reef ca. My ca ranges from 410 to 460ppm and alka ranges from 9.2 - 10.6 dKh. I am not saying that dosing strontium and magnesium doesn't help as I am sure it would. In my case I have never added it. I use reef crystal and do a 10 water changes everyother week. Running 2 X 250 MH 12,000K and 2 X 96 PC 10,000K.

Even my clam shell is covered with it :)


My Site
Indeed, toptank has the toptank when it comes to coralline algae. I have been trying to achieve something like that, with spurts of success. Unfortunately, my coralline algae doesn't look close to yours.

I have often wondered why I need to supplement strontium to get mine to grow. Obviously, some people don't need it. I just see a huge difference when I do.

I also use a 2-part calcium additive (Restore).

I just don't get it?
Hi there !
I'm from Brazil and this is my second time here.
I asked Delbeck about this subject.
I asked him: Can the coraline alge compete for calcium and prejudice the coral's grown ?
He said that he thinks that is a good idea to keep a lot of corals because it's possible that dominate coraline can consume the calcium and it makes you add more calcium than you need to keep your corals healthy.

( I'm sorry about my English because it's not my language ok ?! )

[ ]s
Coraline has its upside, but it can become a plague. I am sick of spending time using razor blades to scrape it off the front. I have noticed that the blue leg hermits and stars eat it off the back.

Good article BTW
Hey O'man can you tell us your water parameters and also your type of calcium imput. THX
Hey kmu:

Prams are: calcium... 380 to 460
alk........3.5 to 4.0 meq/l
nitrate, phosphate, ect are zero, but I only use hobbiest grade kits like fastest and hagen
specific gravity...22 to 24, depends on level of evaporation
I use seachem reef advantage and reef builder. These are great products, but do require monitoring of specific gravity. They will creep it up on you if you are not careful. I also use 2 part liquids like kent or bi-onic when I am in my lazy mode.

IME/IMO the seachem powders are best for raising levels. The 2 part liquids are best for maintaining existing levels.
Greg; I agree with most. However, I have found the more intense the lights, the lighter the coralline colour.
Under Iwasaki,s its a pink/purple and under normal outputs its a darker, deeper purple. I even grew some maroon under normal bulbs. The darker also seems to love actinic colours, which of course is darker.

Magnesium & strontium, do indeed promote growth, of course with good levels of calcium.

One of the best additives for the growth of coralline is a two part ca/alk. supplement. I have had great success with both ESV & C-Balance.

Toptank, these two part supplements contain magnesium & strontium, along with other trace elements. Thats why they grow coralline well.