Thank you. I tried looking it up and got some pretty wierd answers that I wouldn't try because they didn't seem right. One said 1 tsp per CUP and another said 4 tbsp per cup! Then I just got the generic 1 tbsp per 5 gal thing....
Anyway, since I did a water change 2 weeks ago I've been seeing problems in all my male bettas. They just get these holes and rips in their fins :( I know it's not from anything in the tank, and my weekly maintenance is as neurotic as it always has been, so since it started happening right after the water change it must be something in my water. Stupid well water >:( Otherwise they are fine, building huge bubblenests and acting as frisky as normal, but Cassanova seems especially suceptable to it (the others just heal up). So I'll try the salt bath today and see if we can get our water tested soon. Wish me luck that this issue goes away soon.