Vanishing plants

[bigphesta]

I have a 30 gal tank and I have a 24 watt plant light on it, yet every plant in there seems to 'vanish'. I have some Angel Hairs (I think that's what they are called) and a grassy looking thing that I'm not sure the name of (you can identify them HERE if you're good at that thing.

The plants turn transparent then go away. I add some growth additives once a week as directed on the package, I have no CO2 but do I need this, do I have enough light, is this related?

 

[Silly me]

I also have a 29G tank, but mine is currently running on 104Watts..

you'll need 60-90watts (2-3watts per gallon) of fullspectrum light to get good growth.

 

[sinistral]

I've just noticed this thread. Is that mondo grass on the left of your tank? If it is, that could be part of the problem, as mondo grass inevitably dies after some time in the tank, as it isn't a true emmersable aquatic plant.

I have to agree with Silly_Me, you'd need more light to get robust growth.