Plants going yellow, getting holes in them...

[ecto1]

What's going on with my plants? They're all turning yellowish, and some have gotten holes in them, and in general none of them seem to be doing as well as they used to. Any thoughts?

I've been using fertilizer, but I have carbon in my filter. Should I take the carbon out? Also, I'm going to set up a CO2 system today. I'm trying as best I can, but if anyone knows what's going on and what to do, that would be awesome.

 

[r0b3y]

what kind of plants are they??
and remove your carbon.. it takes out some sort of minerals that the plants need, this could be a reason..

r0b3y

 

[Silly me]

size of tank, amount and type of lights.. ??

 

[ecto1]

The tank is a 75g. I'm not sure about the WPG, but it seems like it would be okay because it's really bright. The plants are getting 12 hours of light a day. There's about six plants with this problem - not even sure what they are, but I think they're some type of swords... they didn't come with labels.