Working Out My Lighting Levels.

[Maximumbob]

Hey guys,

I've been playing with my calculator and reading Georges lighting post stickied above.

Basically I have a Juwel Rio 180 with an arcadia I bar above it. I have put 2 of the arcadia T5 Plant pro tubes in it. They are fitted with arcadia reflectors too. I was calculating my light levels and according to Georges list i have 'low to medium light levels. It works out at 1.5 WPG:

2 X 39W tubes = 78 Watts

180 litre tank = ~52US gallons

78/52 = 1.5 WPG

Now I have been growing plants with high light requirement with not too bad results. Now I am confused!

Would the reflectors and the bulb type/quality be making a big difference here?

Any comments/ideas/ insights???

Max

 

[DevUK]

180 litre tank = ~52US gallons

78/52 = 1.5 WPG

180 litres is 47 US Gal I make it 1.65 WPG which might make a difference Then theres your substrate which takes up space further decreasing your amount of water and giving a little higher wpg still.

From what I read this is actually not a bad light level for this size of tank. If I've read correctly, lower wpg on a big tank isn't the same as on a smaller tank, a bit like nano tanks require quite a higher wpg rating than bigger tanks to grow the same plants.

 

[Dave Spencer]

Displacing water with substrate, decor etc. does not affect the WPG. Taking half the water out of your tank will not double the WPG.

The WPG rule is not really a rule as so much as a general guide, and I don`t think it takes in to account T5 lighting with reflectors. However, like DevUK says, 1.65WPG should be plenty of light.

Dave.

 

[DevUK]

Displacing water with substrate, decor etc. does not affect the WPG. Taking half the water out of your tank will not double the WPG.

The WPG rule is not really a rule as so much as a general guide, and I don`t think it takes in to account T5 lighting with reflectors. However, like DevUK says, 1.65WPG should be plenty of light.

Dave.

I figured that if you had less water for the light to travel through it would affect this? I guess substrate doesn't really count then

 

[Dave Spencer]

I think WPG is really quite dated, and I believe there are more accurate methods around. I just tend to go on what I feel will be right for any of my tanks. Use this link from Sam`s signature, but be aware that the figure it chucks out is for very high light, so you can adjust it down accordingly.

http/www.fitchfamily.com/lighting.html

Dave.

 

[DevUK]

I think WPG is really quite dated, and I believe there are more accurate methods around. I just tend to go on what I feel will be right for any of my tanks. Use this link from Sam`s signature, but be aware that the figure it chucks out is for very high light, so you can adjust it down accordingly.

http/www.fitchfamily.com/lighting.html

Dave.

I've gone cross eyed! Still, for my big tank it suggests 133 watts. I'm nearly half way there, lol

 

[Maximumbob]

yeah.. 139 watts for super high light!! hmm... I guess at half as much I got myself medium light!