Before you change any water,how long has this tank been setup?? Is it still,or just begining it's cycle?? If this tank is cycling#1 do NOT change the water.This will only prolong or compleatly stall the cycle.#2,GET THAT ANEMONE OUT OF THERE. The ammo not to mention the nitrites will surly kill it. If the tank is not cycling,you still have a problem with the ammonia at .30. And the anemone still must come out till the ammo settles down..