I tried this treatment before but I can say if it worked or not. Because after the 7th day I still saw RTN issues with some of my Acros. Then I started using the Triton RTN solution. I don't know which one actually resolved the issue or is it a combination of both. However, I am having a massive RTN problem right now where I have lost almost 50% of my Acto colonies, some of which has been in my system for more than 10 years. Needless to say, I don't even want to think about this in terms of dollars. I am going to try the cephalexin treatment again, but this time I think I may have to increase the dosage. And I'll make a concerted effort to do it at night when the lights are out as recommended. I'll keep you guys posted. See the attached images. Dipping them does not help and in most cases impossible because these corals have encrusted onto my rocks over the years. If anyone know where I can buy the tablets cheap I'll certainly appreciate it because getting them from my vet is super expensive