i think youll be safe bleaching or using peroxide in your gravel (peroxide wont hurt your fish if a little is left behind).
there are a lot of options for spare quarantine tanks. you dont have to actually have a tank. i know a lot of you guys are on budgets. heres a good solution. rubbermaid tubs come in good sizes and are CHEAP. i bought 2 18 gallon tubs for i think $4 each at walmart. you have to look out for the ones with the antimicrobial stuff in them, but those tend to be a bit more expensive, so just read the labels. you can keep spare media in an existing filter or even just floating in your tank. keep a spare filter around and voila, instant hospital tank. it is very important to quarantine new fish. an absolute minimum amount of time to quarantine should be 2 weeks. 4 weeks is pretty normal. anything they might have will most likely show up in that time.
there are a lot of options for spare quarantine tanks. you dont have to actually have a tank. i know a lot of you guys are on budgets. heres a good solution. rubbermaid tubs come in good sizes and are CHEAP. i bought 2 18 gallon tubs for i think $4 each at walmart. you have to look out for the ones with the antimicrobial stuff in them, but those tend to be a bit more expensive, so just read the labels. you can keep spare media in an existing filter or even just floating in your tank. keep a spare filter around and voila, instant hospital tank. it is very important to quarantine new fish. an absolute minimum amount of time to quarantine should be 2 weeks. 4 weeks is pretty normal. anything they might have will most likely show up in that time.