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berzer
02-24-2003, 12:12 PM
Recently I have decided to get back into growing plants again in my tanks after some experiments with other things.

My previous experiment left me with 2 - 250 watt Metal Halides that run on off of a dual ballast. I currently have one 75g tank that I am growing plants in. It already has DIY CO2 (which will turn into a cylinder within a month) running into it and from the charts it looks like it has fairly good CO2 saturation. It is planted heavily with mostly stem plants, a few rosette swords, lilaeopsis, and java fern.

500 watts seems like way too much light for a tank this size at 48x18. And it probably is as the water started to cloud/green up a little. And 250 watts seems like just right yet still on the high side where I would like it.

What I want to know is can I go with one 250 watt bulb over the center of the tank and not lose too much light, maybe 4-6" above the surface. I have read that usually MH bulbs only cover about 3 sq foot. So I am a little concerned that the plants on the sides would suffer from the lack of light on the sides (there are currently ludwigias, aureas, and ambuias there now).

I guess my other option is to stick with both bulbs but just raise them further up from the water as they are horizontal pendant fixtures, which I have done to keep the green water from continuing. But I was sort of hoping that I could use the second light for another 75g that I plant to put in the opposite corner.:D

What do you think?

plantbrain
02-24-2003, 1:31 PM
Yea, I think you could do a single light on each tank.
I'd add high light plants near the light and low light plants and such on the outskirts.

500W of MH is a lot of light. I have 350 e ballast w with the 4300K bulbs which are the brightest and it's lots of light. But no Green water. Add detritus and mulm from an established tank and fill the tank to the gills from the start and that will not occur on a new set up unless you do something to stunt the plants.

Regards,
Tom Barr