Hydrogen peroxide is a strong oxidant and it is similar to ozone in that respect . It breaks complex molecules down into simpler molecules. It will reduce the organic loading in your system and increase water clarity like ozone. The by product is oxygen. Fish can handle high concentrations short term (100 mg/l + for an hour).
I had a Malawi tank and dosing dramatically reduced the volume of sludge (bacterial biomass) in my hang on back filter. Nitrifying bacteria can handle a 30mg/l dose once a week (it rapidly degrades, you will see oxygen bubbles everywhere).
I have used 10 mg/l successfully once a week in a reef system with lps. Dose slowly and ensure an even spread of peroxide. I have killed a candy cane by dosing to quickly into a powerhead (concentrated flow of peroxide). The optimal dose for your system would depend on your feed rate (higher feed rate more peroxide). I would suggest staying below 10mg/l once a week. I feed heavily.
When buying peroxide look at the concentration of the active ingredient in the product and calculate the dosage based on the active ingredient. To achieve 1 mg/l use 1 gram per 1000 litres. A 50 % solution would be 2 gr per 1000 litres. Most pharmacies sell a solution that is up to 12.5 %.
Be careful though, you can kill corals with high doses or incorrect application.