I have recently switched over to a salt water tank and I continue to lose fish. Water is fine after running constant tests and bringing to a store for tests. I keep loosing yellow tangs, angel fish and just lost my first clown fish. I have purchased my fish from all different locations to make sure the problem wasn't where I was purchasing the fish. I would appreciated any advice or helpful tips. I have lost over $800 in fish, please help! Thanks in advance.