Optimal lighting

[Sea-agg09]

So I picked up a used 48" wavepoint light yesterday. The bulbs are old, and need to be replaced anyways, so now I have some lighting options. I am wondering what I should do with 75 planted tank. Once I move, it's going to be on automated CO2 (the works), so I want the optimal lighting for some good growth, but look good at the same time. The new light has 4 T5's, so I can play around a bit. I've heard 2 10k and 2 6.7k would be real good, but I wanted some feedback before I go by 4 new bulbs.

I also have the original single T8 that came with the tank (this was a BIG upgrade). I am wondering if it would be worth it to throw in a new bulb on that as well, maybe an actinic. While it is only 48 watts in T8, I doubt I would get much/anything for it, so why not...?

[kwc1974]

From a technical stand point, replacing the bulbs every 12-18 months is general rule of thumb. The bulbs do dimm as they age and lose there effenciancy. I noticed this most recently when I replaced my MH 150W bulbs, one was going out so I replaced it. Onced I noticed the difference in brightness I replaced the other.

[Sea-agg09]

I don't know how old the bulbs are, but I can tell they aren't running at their peak. The whites are definitely not at 10k like they are suppose to.

Regarding the old T8, it was really more a question if that light would even impact the total lighting of the tank. I'm considering using it as an actinic if I go with the 10k/6.7k setup, of even possibly modifying the cord to add a dimmer, and have a fancy lunar light...

[kwc1974]

Long story short yes the additional light will have an impact. Jape much off their peak will determine how much they will impact the overall lighting (obvious). There are some arguments that if the bulbs are too old then they could influence algae, but I have not seen anything to really support that.

I say add them on. The more light the better

[Sea-agg09]

The theory behind that is that the phospors degrade, and so they don't produce the wavelengths they were designed for, which then is not optimal for plant growth. Frankly, the bulbs must be pretty old, and I'm going to end up replacing them all. Now I just need to figure out how to add a dimmer to the old light....