high amonia levels, swamp looking water

Question
I have a 33 gallon 7 week old freshwater tank.  We currently have 9 fish (3 danios, 3 tetras, 1 guppy, 1 platty & 1 silver molly).  We have a cascade 150/200 filter.  We do water changes about every 3 days.  The amonia levels are staying high (0.5).  I did a water change 2 days ago, last night the amonia level was higher and today it is 8.0.  The water is extremely cloudy and green looking and there is a light brown slime on the plants (all fake).  I tested our tap water and found the amonia level to be between 0.25 and 0.5.  Could this be the problem?  What is the best solution.  The tank is in the corner and does not get direct sunlight but we turn the light on in the evening  (abaout 5) and leave it on until 10.  Any suggestions will certainly be appreciated.

Answer
Your tank is still not cycled.

Every time you add more fish that the bio-load can handle, you are mini-cycling your tank again.
Continue with your water changes, add a product called "Seachem's Stability" as per the instructions, and do not buy any more fish.
My guess it that you are also overfeeding, but I could be wrong. Do not allow any food to fall and rot. Make sure all food is eaten.

Also, your filter is not strong enough to handle your tank size.

After you finish with the cycling problem, get another filter. You should try and aim for at least 350 or 400gph on your tank. SO get another cascade 200 or get a single powerful filter, your choice.
However, make sure that whatever you decide, it is critical that you run the new filter AND the old filter together for the first month. This allows beneficial bacteria to colonize the new filter.

One more thing, the tetras and danios are schooling fish. Get at least 3 more of each, after your tank has long been cycled, of course.

-Nick