I Think My Plants Are Dying :( Why?

[s007]

Here is the pic i took from one of my plant leaf it seems to be spreading , and some leafs going brownish and then just come of the stem and float.

What can be the problem? I have CO2, 8 Gall Tank with 28 W light on for 12 hours every day. Do feed my plants with liquid fertilizer.
Can it be cured and how?

Thanks really worried

 

[s007]

no one knows?

 

[aaronnorth]

Take a look at plant defficiencies in my sig

 

[Colin_T]

CO2 in an 8g is bit much, it could be causing the PH to drop too much.
The leaf could be an emmersed leaf that is rotting because the plant is now underwater. Or the plant is not a true aquatic and is dieing. Any idea what the plant is?

 

[aaronnorth]

It doesn't matter what size tank it is to have co2 does it? As long as it's under control.

 

[RadaR]

It doesn't matter what size tank it is to have co2 does it? As long as it's under control.

Absolutely correct.

 

[s007]

They are aquatic plants but i dont know the name of them, The top of those plants are going yellowish and then brown for some reason but al the rest of them are healthy green.

This is very strange i just dont know what else to think. To me it almost looks like Ludwigia Repens and they by nature do that, that top leafs go yellowish and brown.