Old bulbs causing algae???

[dwculp]

I have been battling a HORENDUS algae outbreak that started over a month ago. The algae is brown and scrubs off easy (diatoms probably). I will scrub the tank, change water and the algae comes back over night. Here is the setup:

40 gallon tank
CPR bak-pak 2 skimmer
TBS package - 40 ponds LS and 80 pounds LR
1 X 96 W 10K
1 X 96 W actinic
1 X 96 W 50/50
4 Azure damsels
1 Perc

The tank has been running for almost a year, one of the light fixtures is 12 months old this month.

I have been scrubbing rock and changing 15 gallons of water at a time. My nitrates are close to 0 and virtually undetectable with different test kits and my PO4 is under to right at .25 ppm, temp is steady at 26C , SG is 1.025 and pH is 8.4.

I dont get it and it is really getting frustrating at this point, my tank is UGLY. I have read that as bulbs age they can shift their spectrum towards the red which algae like. I notice that the thickest algae is near the top and thins as you go down. No algae grows in the dark parts of the tank i.e. under rocks etc.... The algae exposed to light will actually produce O2 bubbles.

I have ordered new bulbs and they should be here Tuesday. I pray that is the problem as I cant figure it out!!

Everything in the tank is doing exceptionally well and with my constant water changes I have seen a lot of growth on my rocks and organisims I have never seen before. The look great and is doing great except for the algae!!

[EDIT]
I said the algae comes back overnight but this is not exactly true, it actually recedes overnight and is barely visable on the sand in the morning and begins growing throughout the day.