I think 7% would do ok. For 65% I order it. If you do, be careful .. There are some shady companies that ship you a diluted version. A company called lab alley has been reliably consistent. A little more pricey. Otherwise you can find 65% at any hydroponics retailer. It’s used to keep the water flow free of bacteria. This stuff is unbelievably great! It has so many uses. The stronger stuff does work best. If you can get 35% that’s probably equally good if you use 1 cup… 7% I’d use a cup or 2. If you have any clothes with spots etc, you can use the bucket with peroxide on clothes first. It will remove just about any stain you have without harming fabric or color usually. Wet the clothing with the dilution and wash as usual. Stains are gone! Then use dilution for floor. When done, dump dirty water into toilet, it opens drains without harming metal or plastic. It’s also sold as a drain opener. Safe for septic with limited use. I’ve used it for years without damaging anything. Stuff is amazing.