I have a 14 gallon freshwater aquarium that's been running with fish in it for seven weeks. I just tested my water and it is reading zero for ammonia, nitrite, and nitrate. My PH is is 7.4. I'm concerned because I'm noticing tons of tiny bubbles lingering at the surface, almost like someone poured a little soap in there. I expect some bubbles with this filter because it's the type where water falls out, but this is much more than what I usually see. I did scrub the glass with an algae pad when I was doing a water change today and I also added a tiny bit of Seachem's Flourish for my plants. I'm not sure if these things would cause the excess bubbles. I do have some crushed coral and a small cup of salt in the tank, but hadn't noticed problems with these before. Most of my fish are swimming actively, with the exception of one of my new platies, who has looked stressed ever since the guy at the fish store put her in a bag for me. I wonder if anyone on here might know what the cause of all these bubbles might be and if whatever it is could potentially harm my fish.