actnic light causing algae?

[Sunshine29]

Hey everybody! :)
So I was experimenting with my lights over my little tank (24x4 t5 over a 29 gallon) and I noticed something. When I ran just my whites vs whites and actnic, I had significantly less algae growing on my glass! I used to run both on a 10 hour cycle and I had to clean my glass every second day! If I run just my whites, I find I only have to clean it once every two weeks. Can anybody explain this for me? :confused:

 

[AmberSunrise]

I had a horrible algae problem in my 29g angelfish tank when the lights were on. I left it off for a few weeks and sure enough the algae went away.

So I thought it might be from the water changes and phosguard so turned the lights back on and within days here comes the algae again.

I cant explain it scientifically but I am assuming it has something to do with the wavelengths of that bulb and the type of algae you have growing that likes it.

How old is the bulb? The wavelengths also deteriorate with the age of the bulb. I know I need to update those bulbs they are almost 2 years old but right now my reef tank sucks up all my money hahha

 

[Northstar24]

Amber is right on, as the bulbs age, the wavelengths shift in a way that promotes algae growth. I had t5's over my tank for 7 months and saw a pretty bad cyano outbreak. After changing over to LEDs the cyano has totally disappeared. I assume replacing my bulbs would of had the same effect, I just chose to upgrade to AI LEDs

 

[Sunshine29]

Well, the oddity is that the bulbs are only 4 months old. So I pose the question to all my fellow reefers, can actnic lighting cause certain kinds of algae?