Can old bulbs cause BBA

[tropicalryan]

Like many I have been battling BBA and I have tried almost everything. I have a hagen glo 39 watt x2 t5 HO fixture, the bulbs are both hagen life glo and I have had them for about 2 years. Could this be the reason I cannot get rid of the BBA in my tank. Some people say to change your t5's every year, others say they can go much longer, but could old bulbs contribute to BBA?

tank stats:

-45 gallon
- Co2 via in line atomizer: comes on 2 hours before the lights and my drop checker is yellowish green when the lights do come on
-dosing EI with 50% water change
-lights on for 7 hours
- I also have been manually removing and spot treating with H2O2
- added power head for more flow

[Cardoc]

When I had a bba problem, I cut down on photo period and got new bulbs (I had cheap ones that came in my fixture). Treated with h2o2 and in a few weeks it was gone, so yes I think old bulbs can cause a problem.

[Canuck]

The people who change their bulbs annually or more will claim old bulbs cause algae. The people who don't change their bulbs will say it doesn't.

[HD Blazingwolf]

Bba is caused by multiple factors IMO. Old bulbs isnt one of them UNLESS, they are preventing plant growth.. if plants are still growing good, then old bulbs arent likely a contributing factor

[DarkCobra]

A sudden decrease in light or growth is easy to notice. A slow decrease over two years, almost impossible.

The replacement frequency for T5HO is situational, depending on the plants' requirements and original light intensity. Some may "need" to be changed more frequently than one year only because the light intensity was marginal from the start. Or if you have more wiggle room, less frequently.

I have a dimmable T5HO fixture, and didn't need max intensity from the start. Wiggle room galore. Although my bulbs are 1.25 years old, I've been able to compensate so far by simply turning them up. And I have a spare bulb so far used only to swap in occasionally to see how much the old ones have degraded, which is definitely noticeable when the new is compared against the old. I think they'll need to be replaced around the 1.5 year mark, as I just had to turn them up to 100% to maintain the intended high light.

At two years, your bulbs are probably producing half the usable light they originally did. If you were originally running a high light tank, you're now running medium light. It may not be the cause of your BBA, but I say it's time to change the bulbs regardless!

[danielt]

And to add up a bit on what has already been discussed maybe I'm stating the obvious for some but we're talking about PAR. Your eyes might see enough light but as the bulb degrades so does the PAR output.

As a household light it might take a couple more years until the bulbs will take their last breath but for plants the light it's useless.

From an algae perspective, if the plants are not ok, they will have the opportunity to take over the tank as they're more efficient in less light than plants.

[tropicalryan]

thank you all very much. I think I might as well purchase some new t5 ho's (probably going to go with giesemann aquaflora and midday) since it make sense that the par of my bulbs has probably degraded. Additionally I have tried just about everything else to combat bba- I will report back to see if they do in fact make a difference in a few weeks

[herns]

I change my over 2 year old bulb recently and I see a lot of noticeable growth difference than new.

[tropicalryan]

Originally Posted by herns

I change my over 2 year old bulb recently and I see a lot of noticeable growth difference than new.

I'm hoping this is the answer to my bba outbreak