I've used the Dr Tim's One & Only twice and it worked for me. Cycled in less than a week. I usually add fish very slowly, so I am not sure how strong the bacteria colonies are. I've never had nitrate issues and I even had systems with those dreaded bio-ball nitrate factories. I just got a 240g and am not sure I want to pay that much for Dr Tim's, so I will very likely do the shrimp method. If I go with Dr Tim's, I will do a day-to-day chart so everyone can see.