Andrew, I have more coraline than I could ever want, I scrape the side and it's covered again in weeks. I do notice that my SPS don't grow like they should. While they encrust heavily, they don't elongate at all. This may be due to elevated Ca levels (>500ppm) over a few months, but I do notice that as I drop Ca, the corals are starting to grow, and it's possible the coraline is slowing. If you really want coraline, come by and we can scrap soe off to seed your tank with, this has always helped me.
Nutrient wise, I have really no other algae to speak of, other than some small patches of wafer algae. I don't think it's a nutrient issue.
My 150 used to grow coralne like crazy, even though the SPS needed pruning monthly. However, my 75, with equally strong SPS growth, didn't have any coraline whatsoever. So hard to say, from experience, I have yet to determine what causes it to grow, or impedes it.

My tank had coralline a couple of years ago for a short while. Then suddenly it all died off for some reason and that was the end of that. No coralline on glass/pumps but I still have some on the rock. I'd love to have it grow but I dunno, I guess all my sps are sucking the Ca up too fast.

Hey I've got quite a few dime sized spots on my glass and pumps.
But I've noticed that on the under side of my home-made rock and my base rock (in the shade) coralline is covering everything. Seems to like the shade.
It is growing on everything but it's much faster in the shady areas.
Just an observation.
I'm running 3 250w mh 15000k and pc actincts

Coralline definitely does better in lower lighted areas, I find it used to grow best under my eurobracing and under various powerheads and such. Don't talk to Marie about that though :wink:

It's possible the coralline algae is using the nutrients and thats why you have no other algae.

Something everyone forgets is that everything including sps corals need nutrients of some kind in the water column to grow, if one organism is using it all up before others can grab it then the others growth suffers.
I happen to have a ton of coralline, fantastic coral growth, cyano out my ears and a healthy ball of cheato in my sump. I also have very fat fish who get fed too often :redface:.

I do find different colours of coralline like different levels of light. The pinks and lavenders like higher light and the reds and purples like it better underneath. The branching kind doesn't seem to care and the plating stuff is definitely low light

Marie, what I meant is that I dont think the lack of coraline is due to lack of nutrients, but rather I don't think it's presence means high nutrients.

And I guess what I'm trying to say is... What are you crazy? why on earth would anyone want coralline algae. It sucks up all your calcium and then you have to buy shares in a vinegar company to get it off all your equipment :razz:

I have it growing inside my skimmer, it clogs up the airline that I use to gravity feed my calcium reactor and I even have it growing inside my wavebox :lol:

Thanks for the replies.

I'm still leaning toward the lack of coralline in my case being the result of high nutrients that aren't being picked up on testing. As I mentioned earlier, when I blast my rock I stir up the detritus and it gets caught in some of the hair algae on the LR which I think is what feeds it, but there could be some unmeasured nutrients in the tank that are also contributing to it. I also think this is why briefly adding sand lead to a brief explosion of coralline - the sand acted as a nutrient sink while it was in there briefly.

My Ca is quite high as well Brad (often testing at 500+) and I do notice I get more encrusting than vertical growth. I might try to change my dosing on my dosing pumps to see if I can bring it down a bit and see if it has any effect.

I'm going to put support to that, personally my tank maintains around 380ppm with consistent water changes. Once I started dosing small amounts of kent liquid calcium once a week, I got coraline out the wazoo.

Maybe you want to try some purple-up? ;)

I have it in my skimmer too, and the skimmer is in a separate sump room with a 50w bulb in the ceiling!!