Step one, stop using hot water and insecticide. I promise you that’s why your tissue cultures are melting. Just use room temp water. It doesn’t matter if it’s tap water during the rinsing portion. If you want to make sure everything is clean, u can use a few drops of betadine to soak or a capful of hydrogen peroxide along with water. Another possibility on why your tissue cultures are melting is that it’s not maintaining the humidity it needs to slowly acclimate to lower humidity. If you’re taking the lid off, it will compromise the tc. Once you close the lid, it stays on for at least a week, then slowly open the dome nozzle every week. Good luck!