we have had are fish tank for approx four weeks, we have an internal filter and also a fluval 304 external filter! we left the tank for a week before we added any fish we then added a humbug,4 green chromis and three clown fish, to help mature the tank! the nitrate lvel went sky high within the week and then returned to zero and remained at this level for a further two weeks! two days ago we added a regal tang,although all the fish are eating and behaving normally. my nitrate level has increased to five i am really worried about my fish as i have read that nitrate levels are toxic! please can you advise me on what i should do thankyou loads emma
