I exceed the 4 wpg rule...

300 watts MH over 66 gallon

http://aquarium.planetaclix.pt/aquarium2.jpg

but I guess that 5.73 watts is a little too much...


"Michi Henning" wrote in message
...
"kgrosnik" wrote in message
news:1038841460.311822@sj-nntpcache-3...

Problem: No plant growth, algae covered.

What I have: 75g 48"L x 20"H x 18 D. Flourite/gravel mixture substrate,
(2)
metal halide 175w 6500k/(2) 40 w flourecent plant bulbs.

Hmmm... That's 430W for 75g tank, that is, 5.73W/g. That's too much light,
according to most people's recommendations. 2.5W/g is considered high
lighting, and I'm not aware of anyone ever exceeding 4W/g.

So, with that much light and no CO2 injection, it's not a surprise that
the
algae are going out of control. The color temperature of your metal
halides
is a touch on the high side too. I prefer 5500K to 6000K at most. Any
higher than that tends to encourage algae.

I know the first answer is get a co2 setup, but I had better luck with
(3)
40w flourecent bulbs over the metal halides. Should I use a different
spectrum of light such as 10k?

No, that will only make it worse. The bluer the spectrum of your lights,
the more you encourage algae.

Surely with 350w + 80w light would be
sufficient. (doesn't look very bright, yellow tint, 6500k bulbs) The
bulbs
are about 8-10 in above the surface of the water. I have no problems
with
the fish stock . Can get ph, O2,CO2 readings, if needed, but I think
I've
got a bigger problem. I tried adding pottasium, iron and liquid CO2 on
a
regular basis, but it doesn't do anything. Any assistance would be
appreciated.

Reduce the lighting period to 10 hours. (Any less than 10 hours and your
plants will probably start to wither away after a few weeks.) Add CO2
until you get to 30ppm. But, even with that, I don't like your chances.
430W is simply too much light, I suspect.

Cheers,

Michi.

--
Michi Henning Ph: +61 4 1118-2700
Triodia Technologies http://www.triodia.com/staff/michi