Houdini Cyano algae - thoughts

[carriej]

Hi Folks, I know this is "technically" not algae... But here goes

So... I've got what I believe to be Cyano - it's in two spots; both in the front of the tank. It showed up about 10 days ago. However here's the thing...

Every day around lunch when I go down to feed the fish - I get irritated as it's in full bloom. I go down at night time to feed the fish... And it's gone. It's also not there in the morning.

I run my lighting from 1030-1:00 (blues) 1-6pm full blast (blues, whites, and a purple) and 6-930 blues). The algae appears somewhere around the 1PM mark, and it's gone by 8PM. Going to check and see if it leaves earlier...

What gives? In the evening there is literally none left - the sand is completely clean. Does anything feed off this stuff that might not come out until the daylights flick off? My skimmer did slowly die; however I cleaned out the nest of tubeworms and vermatids from my pump, and it's running again.

Someone told me old bulbs could cause the issues... I do have one older bulb (out of 6), but that is the bulb that's on when it's gone... Plus it's not THAT old. I would guesstimate maybe 6-8 months; while the others are only about 4 months. I do have new bulbs here though and I am planning on switching some out tomorrow during maintenance to see if that improves it.

Any ideas would be appreciated. I have tried pointing powerheads lower; but it doesn't seem to make any kind of difference other than creating a depression in the sand (which also fills with cyano). I am running about 25x tank volume. (3300GPH (not including return) ) on a 130G tank.

I just don't understand why it goes away every night... And comes back for the majority of the day, and gone in the evening.


Here's a pic of it in full bloom...