Originally Posted by Seattle_Aquarist
Sorry that you wiped out your tank, dosing a whole bottle will do that. Hydrogen peroxide (H2O2) is a strong oxidizer like bleach so basically you sterilized your entire tank. When I treat a tank with H2O2 (either with spot treatment or whole tank treatment) I don't dose more 1.5 ml per gallon (approx 1 teaspoon per 3 gallons) and have never lost a fish or plant.
That said, the H2O2 breaks down rapidly, typically in less than 24 hours, into H2O (water) so it is doubtful if there is any left in your tank. If it were me, I would take the opportunity to do a thorough tank cleaning followed by a major (50%+) water change and then restart my tank just like it was brand new.
brand new mean: new aqua soil?? or just try to clean the old soil, which is only 3-4 month old.