Bad Lighting

What kind of substrate? How many watts per gallon of light and what is the Kelvin rating? Do you have any CO2?

You've got some very large diameter substrate which is not the best for plant's rooting and prospering. I would consider either adding some finer material, or replacing what you have with more suitable stuff.
You don't mention how much light you're supplying. But from the look of it, I'm thinking that this may be a nutritional or better, a lack of nutrition that's causing the problems.
Just how much and what type will depend on the wattage.

Len

Well here's what I would do. Firstly I would add more plants, and lots of them. Anacharis, hornwort or even more of the sunset hygro. Basically, good and easy fast growers for now. You have provided a good environment to grow plants with your light levels (finer substrate would be nice as mentioned) but you're not taking advantage of it.

Test your water. Know your nitrate and phosphate levels. What are the plants using? What traces are you providing? A water report for your area is handy so you know what else in in your tapwater, for example, potassium, calcium and magnesium.

At 2.55wpg I'd add a carbon source such as Flourish Excel or set up DIY CO2. If going with CO2 then you have to make sure your KH is at 3 degrees or higher to avoid a pH crash. So KH and pH test kits are necessary to measure CO2 levels in the tank (although it's getting debatable about how accurate this is, but it's still a rough guide).

If you go with Excel, measuring CO2 is out the window but pH, KH and GH test kits are always handy to own.

nepenthes_ak said:

Ok so what i did was basiacly lower the light, cause i saw that the plants that were getting high light had less and less green pigment but the lower parts of them had a nice green color to them

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Lowering the light will make the plants a bit less needy for ferts. When new growth is not looking too good, for me it says that the plants are lacking in something. Your fish may provide enough waste to keep the plants happy. What are your lighting levels now?

nepenthes_ak said:

I will Debate a C02 system, mainly because i heard they do wonders (then i dont have to buy fertalizers right?)

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Plants will always need some source of nutrients. Most people use CO2 because when you get to a certain light intensity (around 2.5wpg) plants become carbon limited. CO2 should be used in addition to ferts.

nepenthes_ak said:

How do i add the substrate Would i have to move all my fish to a smaller tank or something?? And What kind should i use? Could i use small pots instead?

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To add new substrate you would be better off removing fish and keeping them in a temporary home, with filter and heater if possible. You could then get the new substrate in quickly. Some good planted substrate are Eco Complete or Flourite. Eco is almost black and Flourite is a dark red/brown. Eco requires less rinsing. Any pea grained gravel would also work.

nepenthes_ak said:

Also what is KH?

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KH is carbonate hardness. It lets you know how much beffering is in your water.