Lighting Confusion

[Tonyb111111]

Please can someone help me work out if I have the required lighting necessary for high light plants. I have an Aquael 200 litre tank measuring 100w x 40d x 50h. With this I have two 39 watt T5 tubes with reflectors. Looking at the watts per gallon calculation, this works out to 1.47 wpg. However, this does not take into account the type of light or the fact that they have reflectors. Can anyone tell me what affect these will have on my wpg value, and how these factors are calculated into it. The plants I want to grow are stating a requirement of 2 wpg and I do not want to add new tubes if it is not required.

 

[KittyKat]

What plants do you want to grow? I haven't ever heard of any plants having a starting "requierment" as such, especially since most plants can grow well in lower lights with enough CO[sub]2[/sub] and fertilisation.

Also, the closer to the gravel the plant is, the less light it gets, so 1.47 wpg mean quite different things to a carpeting plant and a floating plant, which is why it would be useful to know which ones you have in mind.

 

[Tonyb111111]

Hi, the two main ones I want are Eustralis stellata to replace my cabomba Carolina at the back of the tank. But the main one is Micrantheum Umbrosum at the bottom of the tank in a corner to grow over the end of my driftwood

 

[SO19Firearms]

I wouldn't worry about it.

 

[KittyKat]

I have had both *survive* at lower light, so I think they should be fine at your lighting in the long term, as long as you provide the right amount of CO[sub]2[/sub] and fertilisation.

 

[Tonyb111111]

I have had both *survive* at lower light, so I think they should be fine at your lighting in the long term, as long as you provide the right amount of CO[sub]2[/sub] and fertilisation.

I add ferts weekly and have just started adding Flourish Excel daily, so do you think this will do the trick. I am still trying to find out what the effective wpg is with reflectors and T5's

 

[reignofcheese]

1.5 wpg is high light for T5 bulbs, they are extremely efficient.

 

[m_attt]

reflectors dont alter the wpg calculation

 

[Tonyb111111]

Thanks guys, if I am in a high light situation, will flourish excel do the trick or will I need CO2 injection. I know excel is only 40% as efficient as gas CO2 but I don't want to go down that route.

 

[KittyKat]

reflectors dont alter the wpg calculation

They might not alter the calculation, but they do alter the meaning of the results A tank with a "mirror" (foil/metal) reflector probably has at least 50% more light going into the water!

 

[Tonyb111111]

reflectors dont alter the wpg calculation

They might not alter the calculation, but they do alter the meaning of the results A tank with a "mirror" (foil/metal) reflector probably has at least 50% more light going into the water!

Thanks KittyKat, I guess I have enough light, just need to keep an eye on things to determine whether I have enough CO2