I have recently decided to switch my water conditioner from tetra aquasafe to prime based on the recommendations I have read here on fishlore. All of the advice that I have gotten here has been priceless. But, I have read in a few threads that prime will leave a film on the waters surface. I don't have airstones in either of my tanks, and I have gouramis in both. Also, I am in the process of starting up a five gallon betta tank. My question is, is the film that the prime will leave on the water's surface bad for the surface breathing fish?