I have a 55 gallon freshwater aquarium. We set it up about 3 months ago. We have had high levels of everything for the last 6 weeks. I take my water weekly to petsmart for testing. I use a gravel vac weekly with water change about 10-15%. They told me to use Amo lock and stresszyme and one other that puts good bacteria in. I am using all of these and now this last water change caused it to cloud up really bad, just as it was about clear for the first time in 6 weeks. There is a white scum growing on the glass inside the tank and also a scum floating on top of the water. I have black mollies, gold platys, zebra danios and cherry barbs in the tank. I am losing one fish about every week. I have no algea eater as it died too. I dont want to add fish until the levels are normal. What can I do?