Lighting Spf - Is This Us Gallons Or Uk Gallon?

[Tonyb111111]

Can someone help me out with this as it makes a 20% difference to watts per gallon value, and I am trying to work out if I have enough light for certain plants that I would like. Also, if I need more light, is it a case of just buying higher power tubes or is it more complicated than that
Forgive the title, spellcheck strikes again...

 

[thereverendturtle]

It's US gallons. To get more light, you need not only new bulbs but a new ballast as well.

 

[Tonyb111111]

Bad news, that leaves me with 1.5wpg when i need at least 2wpg to grow Micrantheum and Eustralis. Thuought i may have got away with the 1.8wpg it calcualted out as using UK gallons. Thanks anyway

 

[thereverendturtle]

How tall is the tank and what kind of lighting are you running? Could make a difference.

 

[Tonyb111111]

Hi again. They are duel Aquael T5/D and the tank is 50cm deep, how does this change the light requirement? I am aware that T5's are better than some others for plant growth, so does the type of light affect the wpg, is there a correction factor for the type of light. So many questions, sorry.

 

[thereverendturtle]

Yes different bulbs produce more PAR. HO T5's are going to be better than an equal amount of T12 imo. But the depth of the tank has a lot to do with how intense the light is, under 16" or so 1.5w would be about the same as 2wpg on a 20-22" tall aquarium.

 

[Tonyb111111]

So do you think I should upgrade to next size up, which I think is 54w. This will give me 2.08wpg of T5's which should be enough for any plant, but may require CO2 addition as well.
Should also mention that both tubes have reflectors, does this also make difference?