Fish In Cycling

Hello, ME AGAIN 😅 I am currently doing a fish in cycle since I got my black moor from a 5gal to 36gal tank. I’ve been testing every other day with API freshwater master test kit. Ammonia has been reading 0.25ppm but just came up closer to 0.5ppm. Nitrite has consistently been 0ppm and NitrAte has been anywhere from 10-20ppm. I’ve been doing a 10gal replacement each time (so a little over 25%). Should I be switching out more than that? I’m about to start siphoning out water to do a change. Also, how do you dispose of the water in test tubes? I’ve noticed if I pour them all together in the drain, there’s an odor and not sure if I’m slowly hurting my lungs or not 🥲

ALSOOOO I’ve noticed he’s had LONG (like 0.5-1”) poops so I’ve had him fasted since yesterday AM which I’m sure isn’t helping the cycle? Also, planning on feeding peeled cooked peas, how many should I feed before going back to food? And I’m worried they may be to big because he’s a smol baby