Thumb rule of using Ozone, if the skimmer smells like a thunder storm coming up, it's too much. If you have a laser printer it probably releases more Ozone each time you print. Good comparision, if your skimmer smells like your printer/copier than you are using too much. Keep in mind Ozone is highly reactive and in a skimmer it will react at once. Of course, it's toxic and using more than is needed in a tank has effects on its inhabitants. I am using about 2-4 mg/h and I don't smell anything here nor see any side effects in the tank so far. Nor on our cats living inside or on me. Well, I am special though ;-)
For the garlic, you can press fresh garlic out, but you can't keep it long as in preparing garlic for a week or such. Alliin/Allicin are pretty unstable and react quick. For the vitamines, as mentioned before, I am using at times a children vitamine mix plus this
stuff Ultra-Min/s. You can soak your food in it or just drop some into the water. The corals like it, too!
And again, fresh veggies and fruits. Don't underestimate that for the vegitarians in our tanks. Sure, you have to try out which your fish like best, but sure worth a try and the fish will thank you.
For the garlic, you can use a garlic press and then put it into a towel or such and press the liquid out. Some fish even seem to eat complete garlic pieces. You have to try out.
And you don't have to get your fish out off the tank there, Juan. Won't help anything at all. As I said before, each tank has Cryptocarion irritans in it, every fish, too. No need to put them into stress by removing them from the tank. Leave them be, feed them well. You might try the UV but as said before, it won't show effects at once, but sure helps to sterilze the tank in the long run.