Tank Size And Lighting Requirements

[loach boy]

originally posted in newbie area but as I've had no responses I though it may be better here. Apologies if not - I'm new to this forum stuff.

can someone tell me how to work out my tank capacity? I know to multiply lengthxwidthxheight but do I use the physical tank dimensions (internal or external) or the volume of water (allowing for unfilled portion at top/substrate etc without getting too concerned over various displacements of bogwood etc)?

for example
If I use tank dimensions (72"x18"x15") this works out at around 320 litres or 71ukg/85usg
If I use the water volume (approx) this works out at around 250l or 55ukg/66usg

If I'm then working out my lighting requirements (aiming for 2wpg planted tank) this can make a big difference in my requirements

Also, how much difference do reflectors make (is it better for less tubes but reflected or more tubes unreflected - limited hood space)

thanks

 

[lljdma06]

I gave a response over at the Newbie section. Just happend to be there today.

http/www.fishforums.net/Working-Out-Tank...ty-t197237.html

llj