Tank conditions?

i have had my tank now for 6 months and i'm still having trouble with the nitrates, anommia is fine, the tank size is 125L. i do water changes everyday from 25L out to 30L i have tried adding prime which the stockisk gave me but the levels are still high. on the second colour on the card (tetra test) instead of yellow its orange. my fish at the monment are fine, the fish in the tank are 2 clown loach, 1 molly,1 red tailed shark, and 2 fry (mollies) so i know there is no overcrowding, i don't know what else to do so help any help please?