Odd Coralline Algae Question

[sleeri]

I've got kind of an unusual coralline algae question. I really don't have very much trouble encouraging the growth of this attractive purple stuff, but the odd thing is that it won't grow on the top 4" inches of glass in my tank. There's a very definite border and it looks kind of odd. Absolutely no Cor. growth above the 4" mark (lots below). I can post some pictures tonight if this is a confusing description. I'd like to fix this visual issue if at all possible. I read about this problem in the Book of Coral Propogation. Anthony C. thought it might be due to light shock during water changes. Has anyone else had this same problem? What did you do to fix it?

[David Grigor]

It is not unusal for coraline for grow predominately in low ligth conditions so could very well have to do with amount of light bouncing off the glass that high up that doesn't encourage to grow.

My personal preference, I like the cleaner look so I don't encourouge coraline growth ( ie: scrap it off ) on anything other than the rock ) so it's really a non-issue for me.

[redlion4]

Our 55 is the same way. It is most certainly linked to water changes in our tank. Every now and then the corraline creeps up above the line. After the next water change, it quickly reverts right back down.

Never tried a water change with the tank lights off....if it was light related, turning off the tank lights during the water change should help.

Then again, it might simply be related to exposing the corraline to air while doing the change to. No easy work arounds for this. I guess if you had a large enough sump, you could perform a water change by only removing and adding water from an the sump. This would leave the water level in the display tank unchanged. Our 10 gal sump only has 3-4 gallons of water in it. A 10-12 gallon water change forces us to drain water from the tank.

Ryan.

[Buckweet]

I concur. I've got a 72G with tons of coraline (right below the water change low point) above, I get the occasional growth, but I would definitely agree that its the water (or lack there of it) that is causing this reaction.