My friend was using reef crystals and always had some spots of dyno/dino ( stringy and bubbly ) in his tank. Anyway only because we bought a bunch and got a good deal, he switched to tropic pro and after a few water changes it was gone. He never considered the salt a problem but due to blind luck he found out. I couldn't tell you if all reef crystals salts would of made him have the dyno because he bought all 3 buckets at once so maybe that batch was high in somethin bad? Who knows. I Think you should try a different salt for a few water changes and see what happens. Then at least you can eliminate your salt as the problem for sure.