It's my first time, be gentle

Fought root rot/res/nute issues all week, but seemed to have turned the corner. Nice steady growth. Cleaned the res hard at the start of the week and continued to treat with H2O2, and switched to Lucas Formula for nutes along the way. I added ~30mL of 3% H2O2 daily for 4 days before the smell seemed to disappear and roots recovered. Afterwards double dosed the hydroguard again. Noticing very dark and shiny leaves with some clawing. I hadn't been measuring the EC in the res and figured I burned the plants. I replaced 1 gal of the res with pH'd tap water to reduce the EC/PPM. Did not take exact measurements. My notes get thinner from here as I had too many plants going at once to properly document this first attempt.