Daniel wrote,
I cannot seem to be able to keep my nitrites down........

Sounds to me like you don't have enough filter media for the bio-load!

guppies are dieing off approximately one every two days......
and today the silver dollars aren't eating.....
guppies aren't eating nearly as much......

*If* it were nitrite poisoning, at least some of the fish would be
showing red streaks on their bodys, they become listless, gasp, hang
near water outlets, tan or brown gills with rapid gill movement (brown
blood disease - forms methenoglobin, which renders blood unable to
carry oxygen, so the fish die from suffocation)... I don't see it to be
nitrite poisoning - if it was you would have a *lot* more fish dying
than one every other day, and the largest fish (silver dollars) would
have been the first to die! Something else going on in the tank - being
overpopulated, I would suspect a bacterial infection. Skin and gill
fluke infections can cause the same symptoms you outlined and can also
be due to overcrowding....
Getting back to the high nitrites - a half tsb. of salt per gal.
(0.5ppm) will help the fish. Stop feeding untill the nitrite level
drops. A product called Prime bounds nitrite up to 24 hours, rendering
nitrite non-toxic (or not near as toxic). How high is the nitrAte?
............ Frank