"Try 70-90 lumens ... for most FL's."

My original assumption was a bit lower than that. However, when I
started checking with local aquarists, I discovered that most
were running 18-24" T12 lamps which are less efficient even when
new. I also discovered that most replaced their lamps only when
they failed, which cuts lumens further by typically 20%.

Hence my request for real data on a broader scale than one local
club.

"(a poor measure of PAR BTW) "

I agree - see http://sankey.ws/plantlumen.html

It's a very rough metric. In one sense it'd be easier to convert the tank
to gallons then use the existing rule.

You're in Canada and so am I and while this is 100% a metric country,
aquariums are still sold in gallon sizes.

Watts per foot or square meter might work for you, but as Tom points
out depth needs to be taken into consideration.

But, it's a rough metric and has always remained a riough metric because
it's not that important. After a while you'll know what you're doing more
and have an innate feel for it.

What size is the tank and what lights do you have on it now??

--
Need Mercedes parts? http://parts.mbz.org
Richard Sexton | Mercedes stuff: http://mbz.org
1970 280SE, 72 280SE | Home pages: http://rs79.vrx.net
633CSi 250SE/C 300SD | http://aquaria.net http://killi.net

On Mon, 24 Apr 2006 22:12:15 +0000 (UTC),
(Richard Sexton) wrote:

It's a very rough metric. In one sense it'd be easier to convert the tank
to gallons then use the existing rule.

You're in Canada and so am I and while this is 100% a metric country,
aquariums are still sold in gallon sizes.

Watts per foot or square meter might work for you, but as Tom points
out depth needs to be taken into consideration.

But, it's a rough metric and has always remained a riough metric because
it's not that important. After a while you'll know what you're doing more
and have an innate feel for it.

What size is the tank and what lights do you have on it now??

When getting so precise, doesn't the depth of the tank have to be
considered as well as the volume?

dick

In article ,
Dick wrote:
On Mon, 24 Apr 2006 22:12:15 +0000 (UTC),
(Richard Sexton) wrote:

It's a very rough metric. In one sense it'd be easier to convert the tank
to gallons then use the existing rule.

You're in Canada and so am I and while this is 100% a metric country,
aquariums are still sold in gallon sizes.

Watts per foot or square meter might work for you, but as Tom points
out depth needs to be taken into consideration.

But, it's a rough metric and has always remained a riough metric because
it's not that important. After a while you'll know what you're doing more
and have an innate feel for it.

What size is the tank and what lights do you have on it now??

When getting so precise, doesn't the depth of the tank have to be
considered as well as the volume?

Not as much as you'd think/maybe/a little/eh.


--
Need Mercedes parts? http://parts.mbz.org
Richard Sexton | Mercedes stuff: http://mbz.org
1970 280SE, 72 280SE | Home pages: http://rs79.vrx.net
633CSi 250SE/C 300SD | http://aquaria.net http://killi.net

In dealing w/ wattage, what adjustments do you make for height?
I have 120 G aquarium with 2 ft. height -

Were the aquarium say 18 inches tall instead of its actual height, would
that affect the calculation of watts/gallon?

Thanks in advance,

Mitch Edelman

On my planted aquariums i use 4ft t8 fixtures and combinations of phillips
f32/natural sunlight and f40dxplant and aquarium builds, with great success
2 bulbs on each 45 AND 4 bulbs on my 120
"Richard Sexton" wrote in message
...
It's a very rough metric. In one sense it'd be easier to convert the tank
to gallons then use the existing rule.

You're in Canada and so am I and while this is 100% a metric country,
aquariums are still sold in gallon sizes.

Watts per foot or square meter might work for you, but as Tom points
out depth needs to be taken into consideration.

But, it's a rough metric and has always remained a riough metric because
it's not that important. After a while you'll know what you're doing more
and have an innate feel for it.

What size is the tank and what lights do you have on it now??

--
Need Mercedes parts? http://parts.mbz.org
Richard Sexton | Mercedes stuff: http://mbz.org
1970 280SE, 72 280SE | Home pages: http://rs79.vrx.net
633CSi 250SE/C 300SD | http://aquaria.net http://killi.net