Corraline turning white at top?

[Adam113]

Went to the beach for the weekend, came back today and both tanks are doing great. Everyone ready to eat and everything looking good. I only noticed one odd thing. At the top first inch or two of my 29g cube, the corraline is white. What could cause this?? Is a very defined area that is white, and the rest is the pretty purple that it's always been.

 

[Tautog]

Check your Magnesium level, this happen to me last summer. Check water temperature, over 84 is a problem. Coraline depletes your Magnesium

 

[Adam113]

Check your Magnesium level, this happen to me last summer. Check water temperature, over 84 is a problem. Coraline depletes your Magnesium

Any idea why it'd only be at the top?

 

[Flippers4pups]

Have you changed your light intensity? Changed bulbs? Most coraline algae strains are light sensitive and an increase in par can cause it to bleach.

Also, another reason it may have died back, but only at the top, could be a power outage. If the power went out and the waterline dropped down enough to expose it to air. This could only happen if you have a sump and it syphons enough to expose it.

 

[Randy Holmes-Farley Verified Community Expert]

I agree that the lighting may be too bright for the type of coralline present there. In many tanks, coralline does not grow best in the brightest light.

 

[Adam113]

Have you changed your light intensity? Changed bulbs? Most coraline algae strains are light sensitive and an increase in par can cause it to bleach.

Also, another reason it may have died back, but only at the top, could be a power outage. If the power went out and the waterline dropped down enough to expose it to air. This could only happen if you have a sump and it syphons enough to expose it.

Thanks guys! I checked this morning and it looks like I must have accidentally clicked a few more hours on my timers with my foot at some point before we left for vacation. The lights were on another 3 hours more than usual. All I can think of. I am going to cut pumps off today and see how low the water goes as well. May have had a power outage for a few hours maybe one day...