I strongly urge not to use chemical tablets in your tank, especially since you have live rock. First how long has the tank been set-up? How much live rock do you have? How much lighting do you have? What kind of lights? What kind of fish? Are you running biological filtration in your two filters? How much water movement do you have? Do you use R.O water for make up and water changes? And what is the PH, Nitrite, Nitrate, Phosphate, Alkalinity, Oxygen levels.
These facts would be appreciated. I have had slime algae in two tanks. 90% of the time its because of phosphates. Use R.O. water for everything, clean your filters every week, if your light hasnt been replaced in 6-8 months..replace it, and upgrade your protein skimmer. Also if your fish are heavy feeders (e.g. Tangs, angels, lionfish, triggers, morays, or big wrasses) then you should cut down on the feedings.
Sam Reef