[ct60g]

Hey all, I had a quick question about the amount of light in my aquarium I was hoping someone could answer.

My tank uses a 2 x T8 bulb setup, so my light level is fairly low. I'm wondering how long I can / should keep my lights on each day?

I never really checked beforehand, but I assumed that having lower light output meant I could keep them on longer, but I thought I would ask anyways to make sure. I run my lights for 12 hours / day. Is that too much, despite the lower light intensity?

 

[Kathyy]

I ran 12 hours with bright light for years. Noticed some stem plants were closing up several hours before lights went out so I dropped the hours lit until they were only closed a short time before lights out. If you have any stems, look and see if they close, if not then that's fine. Other than that if the plants are growing strong and algae isn't a bother then you got it right.

 

[Edward]

... Noticed some stem plants were closing up several hours before lights went out so I dropped the hours lit until they were only closed a short time before lights out.

With so many light fixture types today, MHs, CFs, LEDs, timers and dimmers … what if this is a better light energy indicator then PAR and hours?
What do you think?

 

[Kathyy]

This has been brought up before and posters wrote that the plants just closed up earlier as they adjusted to the day length. I found that 8 hours was about right for my stems but other stems likely would have their own ideal lighting period plus of course you have to have those plants in the tank! I remember Myriophyllum and Rotala responding to light for sure, maybe hornwort. And while the plants were happy I still had BBA.