Why is the water in my fish tank murky?

I bought the tank 3 days ago (10 gallon), have already done a 50% water change and I've been adding necessary bacteria daily as well as been using a Ph balancing formula. I currently only have one fish and a filtering Bamboo Shrimp. (I'm waiting to add less hearty fish until the cycle is complete). The water was perfectly clear until this morning, right after I added a new tetra submersible water heater. Is this the problem? is it harmful?