Coralline Issue....What am I missing?

tcreeftank · Oct 10, 2012

My coralline algae has stopped growing altogether. I have checked almost everything I can think of and read almost every thread on the topic and have yet to find an answer. All water parameters are in line. Had a small nitrate spike a few weeks ago but now have that in check. Is it possible that the nitrate spike caused this die off in coralline? I have tried almost everything and am hoping someone has had a similar problem and cant point me in the right direction. I am sure I am missing something simple but my brain is fried on this topic haha.

Tank:
210 gallon
Filtration:
100 gallon sump
carbon and gfo reactors
octopus 200 skimmer
Lighting:
3 AI Sol's
Water Movement:
MP40W
Koralia 5

About 400 lbs of live rock mixed reef with lps, sps and softies. Any help would be greatly appreciated!

Pkunk35 · Oct 10, 2012

What's your alkalinity and calcium at?

tcreeftank · Oct 10, 2012

Alkalinity hovers between 7 and 8dkh and calcium is always right around 420-450.

-Logzor · Oct 10, 2012

Low magnesium will slow coraline algae growth, as will elevated salinity. If your lighting is too intense that will also cause issues.

tcreeftank · Oct 10, 2012

Logzor - Salinity is always at 1.025. I run 3 AI Sol's with the whites at 50% and the blues at 65-80%. I will try turning down the lighting to see if coralline growth improves. I am going to run out and grab a new magnesium test kit tonight as the kit i have now is older and may be giving me false readings?

-Logzor · Oct 10, 2012

Which test kit are you using? I found that the salifert can be kind of tough to read, unless you're under consistent direct light. Don't use this test kit near the aquarium the blue lights will disrupt your ability to determine when the color change occurs.

If you did a water change and the coraline was exposed then that may have killed it.

tcreeftank · Oct 10, 2012

I have a salifert test kit. I always get a reading of 1200 for magnesium. As far as water changes go, I always drain from the sump down in the basement so the water level never drops in the DT.

Downbeach · Oct 10, 2012

I would have to believe, that with your Ca and Alk at those levels, your Mg is within an acceptable range. You could try adding a little kalk to your top off water.

What is your pH?

Dowtish · Oct 10, 2012

Most tanks I have seen with LED's dont have much coraline growth, if any at all.

tcreeftank · Oct 10, 2012

pH is consistently 8.0 - 8.2

Downbeach · Oct 10, 2012

What salt mix are you using? What do you use to measure your salinity? Is it calibrated?

tcreeftank · Oct 10, 2012

I use IO Reef Crystals and use a refractometer that I got from Marine Depot. I calibrate it about once every 60 days.

STL · Oct 10, 2012

Dowtish said:
Most tanks I have seen with LED's dont have much coraline growth, if any at all.

I have crazy coraline growth both in the tank and in the sump near the lighting. All my lighting is LED - the display tank is lit by Radions, the sump refugium by Ecoxotic stunners. The Radions have a broader spectrum than the AI's, but the stunners certainly do not (one is a 12k white, the other is blue - left overs from an old tank, more than sufficient for a 'fuge) - so I'd almost rule out LEDs unless it's an intensity issue. I run my Radions pretty high, though, so I would not think that would be the case either.

Are you seeing good coral growth? If not, maybe raise Alk a little over 8.

I use automated dosing of 2-part as well as a little kalkwasser in the auto-top off system, so kalk may be something to try as mentioned above.

With my prior tank, I didn't have much coraline growth until I added a tuxedo urchin. He's still with me, and in the current tank. Tux urchins are coraline predators, but I once read a theory that the scraping action by the urchin releases coraline particles that then form colonies elsewhere.

Pkunk35 · Oct 10, 2012

I get pretty good coralline coverage from LED, not sure if the rate would be considered fast or slow.

If you were getting coralline growth before then your lights are ok. Are you sure it stopped growing? Maybe it just growing slower or less noticeable because of the all the growth already there?

I like the ideas of adding kalk drip and raising alk over 8. Both of these helped me to get better coralline growth (along with RO/DI water which i assume you are using). I also think high flow aids in spreading coralline. Also, dust your rocks often.

Other than that, patience is key!

tcreeftank · Oct 10, 2012

I see great coral growth. I had good coralline growth with these lights on this tank until recently so i doubt that it is as i havent changed the lighting program. I will try adding some kalk to my top off water to see if that helps. I do have a large long spined black urchin that I have always suspected of devouring my coralline but could never prove it. There is no coralline in the areas he cannot get to either though so not sure if that would be it.

Troylee · Oct 10, 2012

-Logzor said:
Low magnesium will slow coraline algae growth, as will elevated salinity. If your lighting is too intense that will also cause issues.

This!!! Your mag is low most likely and lights are to bright... I can only grow coralline in shaded areas myself..

Downbeach · Oct 10, 2012

Urchin's are known coraline grazers.
Sea Urchins, A Testy Subject by Ronald L. Shimek, Ph.D. - Reefkeeping.com
Sea Urchins: A Chemical Perspective by Randy Holmes-Farley - Reefkeeping.com
[url]http://saltaquarium.about.com/cs/aboutjanitors/a/aa052899_3.htm
[/URL]

mcarroll · Oct 11, 2012

tcreeftank said:
Alkalinity hovers between 7 and 8dkh and calcium is always right around 420-450.

tcreeftank said:
Logzor - Salinity is always at 1.025. I run 3 AI Sol's with the whites at 50% and the blues at 65-80%. I will try turning down the lighting to see if coralline growth improves. I am going to run out and grab a new magnesium test kit tonight as the kit i have now is older and may be giving me false readings?

tcreeftank said:
I have a salifert test kit. I always get a reading of 1200 for magnesium. As far as water changes go, I always drain from the sump down in the basement so the water level never drops in the DT.

You have a plethora of things all contributing to a slightly stressed environment...the coraline are being choked out.

7dKH is about 2.5 meq/L....that's definitely a low that can allow pH swings that can be severe enough even to affect coral, let alone coraline algae.

I can't attest to the specific settings on your AI's, but as others have mentioned, in bright light scenarios its not uncommon to see little-to-no coraline except in the shadows. Turning down the lights seems like a good strategy.

1200 ppm Mg is pretty low....maybe even low enough that your alk and calcium readings aren't as true as they could be. (Conditions might be worse.)

I would start with a few large water changes, coupled with testing and dosing a little Magnesium supplement in between to "slowly" get the numbers back to where they should be in a hurry. With any luck, the Ca and alk will be balanced out with Mg after a couple good water changes and rounds with the test kits. You will want to have some two-part on hand just in case.

-Matt

Downbeach · Oct 11, 2012

With these reading:

Salinity 1.025
pH 8.0 - 8.2
Alk 7 - 8 dKH
Ca 420 - 450
Mg 1200

I don't see a problem with your water parameters. What are you using for test kits for your Alk and Ca? How old are they? Maybe it would be a good idea to get a second opinion.