I've had bad experience with whitespot cure and rams, I've had whitespot a few times when I failed to quarantine new fish. The most successful way I've gotten rid of it is crank the tank temp to around 30-32 degrees (do it slowly, and same for when you reduce it again) and leave it like that for a week or so. I haven't lost any fish by increasing the temperature and it's killed the whitespot. I have 2 blue rams, glow light tetra, black neon tetra, 3 otto's, and 2 golden bristlenose in my tank.
**EDIT** It's really worth investing in a quarantine tank.