I have 300litre tank with 3 platty, 5 neon tetra, 2 seprae tetra, 3 black widow tetra’s, 1 female guppy, & 3 black neon tetra’s my neon getting white spots as i used 100 drops of wunder white spot cure not sure will it help my neon tetra get better or do i need to add rest of 200drops?