I have a new tank 5wkS old, heavily planted. At 2wks it was cycled, Then put in too many fish,:redface: reduced fish population down to 3 plus frog, got ammonia down from verrrry high to .5 but ammonia levels won't drop past this. Why is this? It is making me crazy. All fish and frog in tank accounted for and living. I have made sure there isn't alot of dead leaves on the bottom and filter isn't overly dirty. What else? janeen