T8 to T5 - is 4x80w too much for 5' tank?

[LindaN]

I've been reading many of the discussions regarding quality and type of lighting but still feel my 5x2x2 tank needs more light as I can't grow the more light dependent plants such as Glossostigma and other small carpeting plants. I have an old Arcadia luminaire with 3x54w.
The quartz gravel has a layer of Deponitmix professional, use pressurised CO2 and feed Seachem plant food twice a week so now I've invested in all this I think I might as well get the lighting right.
The new luminaire for a 5' tank (1500mm unit) would have 4x80w but this sounds like it may be too much so I wondered if the shorter 1200mm unit with 4x54w would be better even though it may fall a little short at the end(s). There is quite a big difference in quantity of light between the two.

 

[Henry]

Save your money and spend it on better circulation for CO2 distribution. Also, invest in some EI fertiliser from aquariumplantfood.com. Glossostigma loves CO2. It carpets in my 15" deep tank with a single 24w T5 over the top, simply because it is supplied with unlimited CO2 and nutrients.

 

[LancsRick]

As above, CO2 tends to have a much larger effect than lighting. 3x54W is plenty of light. As above, full EI dosing may help (although that is more to avoid deficiencies than to speed up growth).

 

[sciencefiction]

As above. I experimented with some glosso in a low tech tank because I got it for free. It's not exploding in growth but has been carpeting. Sadly the pleco, corys and malaysian trumpet snails are having fun with it and uproot half of it but the light is 135W LEDs over a 100G tank, soil base no CO2 or ferts. The distance of the light from the surface is shown on the pics below.
My point is, light could not be a major factor because my glosso doesn't get much of it from what I can tell.

Som pics: