You also might want to look fruther into stress issues.. For Example, a breeding pair of kribs can really harass other dwarf cichlids like the Rams. You also might want to take reading of your water parameters 4-5 times a day for a few days. With Co2 injection, your tank can become very unstable and pH swings might be causing these outbreaks.
I agree. ich can often be present in a tank but a healthy, unstressed fish can keep the disease dormant with its immune system. however, when a fish becomes stressed the immune system will not be as strong and that's when disease can take over. adding medicines will treat the symptoms, but will not address the real problem. you need to figure out why your fish keep getting stressed. if you can figure that out and correct the problem then the ich should go away. I'm going to second the idea to take water readings several times a day to see if there are fluctuations in the ph, kh or anything else that could be causing stress.
aquarium salt is supposed to reduce stress so adding salt and the increase in temp should help cure the stress for now. however once the ich goes away, if you stop adding in salt during water changes without correcting whatever the problem is then the ich will come back again.