Hi have recently started up a new 400 litre tank in addition to my 190 litre and hav naturally had ammonia problems. the ammonia is currently at about 1.5 mg and the few fish that are in it seem okay . i have been adding ammonia remover but as my tests show , the ammonia remover has done buggar all. so i have put the external filter from my 190 litre into the 400 litre. the filter is well established with bacteria. will this cure my ammonia problem and how long can i expect it to take . many thanks !