Lighting

[firefly]

O.k., I'm wanting to do a 125g planted tank (72"X18"X20"). I've been looking at lighting options, and I"m learning that to get 4wpg (for a high light tank) it could easily cost more than the tank!! That is definitely more than I want to spend on lighting. Do I really need 4wpg, or could I do 3wpg or so and be ok? I'm wanting some higherlight plants, but I do like the lower light ones too...

I did find a site called www.hydroponics.net, and it has some metal halides at good prices for wattage, but are these the right sort of lights? They are designed to grow plants, but mostly terrestrial ones... None of the lights are really long enough for the whole tank, but I could center one over the tank, and have a high light center and lower light sides. In the economy section, I could get a 1,000 watt light, but that woudl be 8wpg, I think that's over kill. I could also get a 400 watt light, about 3wpg (a touch more). I could go with two 250watt lights, and cover more space on the top... (I would hang these lights from the ceiling and make sure they weren't so close to the tank to heat it up too much...)
Any thoughts on this? I would also be willing to do PC lights (thought I probably would wind up going that route, but its sooo expensive...). Any other thoughts for inexpensive quality lighting?

Emily

 

[ashdavid]

I did find a site called www.hydroponics.net, and it has some metal halides at good prices for wattage, but are these the right sort of lights? They are designed to grow plants, but mostly terrestrial ones... None of the lights are really long enough for the whole tank, but I could center one over the tank, and have a high light center and lower light sides. In the economy section, I could get a 1,000 watt light, but that woudl be 8wpg, I think that's over kill. I could also get a 400 watt light, about 3wpg (a touch more). I could go with two 250watt lights, and cover more space on the top... (I would hang these lights from the ceiling and make sure they weren't so close to the tank to heat it up too much...)
Any thoughts on this? I would also be willing to do PC lights (thought I probably would wind up going that route, but its sooo expensive...). Any other thoughts for inexpensive quality lighting?

Emily

First I would go with the two 250w lights if you can, I could not access the site but if you can find out the kelvin rating that would be helpful. Try to get a light bulb that has a kelvin rating from 5000k to 10,000k preferably 5500k to 8000k, but this is not essential. Why I say two lights is b/c MH lights tend to have light concentrating directly below the bulb and it get weaker as the light tapers out to the sides of the bulb. As for distance if you use 250w bulbs I would go with a distance of about 10"-15", if you go with a 400w bulb I would say about 14" to 20" away from the water.Unlike terrestrial plants too much light can be detrimental, but this is only in extremes, so I would not worry about that with what you have , even if you put the bulbs only 1" from the water. I hope this helps.

 

[firefly]

Thanks ashdavid! I was kind of leaning towards the two 250 lights (even though it costs more), as I could get the light more evenly spread across the tank. I know that there are some lower light plants (That may just go in my 2wpg tank instead) that would need to be shaded by the higher light plants, but that could easily be arranged. As for having the lights above the tank, that should also work. I've got a drop ceiling in my apartment, and was just planning on stringing a hanging cord through the grid for the lights. These lights are much cheaper than anything I've found elsewhere, makes me wonder just a bit, but it should be fine. I have also found MH bulbs can be expensive too, but I can find the right bulbs for these elsewhere if need be. However, since they are plant bulbs, I belive they are around 6500 K. I'll have to recheck that though...

Emily