When added to water containing algae, H2O2 breaks down into water and oxygen, releasing free oxygen radicals in the process. These free oxygen radicals can then react with and destroy the cell walls and membranes of algae cells, causing them to die off.
Treat the entire tank with 3% hydrogen peroxide or 10% bleach. Leave the solution in the tank for a 2-3 hours with the filter running to keep up circulation. Drain and refill the tank at least 3 times to remove any remaining traces of bleach/hydrogen peroxide and algae.
Depending on the algae species, we recommend different dosages: In the case of blue-green algae: 8 to a maximum of 15 ml of the 3% solution of hydrogen peroxide per 50 liters of water. In the case of green algae: 25 to a maximum of 35 ml of the 3% solution of hydrogen peroxide per 50 liters of water.
Start with 2-3 ml of 3% hydrogen peroxide per gallon of water, up to 4ml per gallon max. Note that this is per gallon of water, not the tank size, as the rocks, decor, fish, etc. can take up volume. You can also spot treat up to maximum dosage by turning off the filter.
The truth of the matter is: hydrogen peroxide is another dangerous chemical just like chlorine. This particular system requires high levels of hydrogen peroxide to be effective. At these levels it becomes an irritant and will oxidise skin, hair and swimsuits. It can also cause respiratory problems.
It is advised to add the hydrogen peroxide, then let the pump run 6 hours before swimming so it's fully incorporated and the percentage is at a safe swimming level.
A 35% concentration of food grade hydrogen peroxide is most commonly used in swimming pools and spas. Some users prefer a 50% concentration. This concentration is much higher than the 3% concentration used for medical purposes.
The dark decay of hydrogen peroxide followed first-order kinetics with half-lives of 7.8 hours (unfiltered lake water), 8.6 hours (filtered, 5 µm), 31 hours (filtered, 1 µm) and >24 hours (filtered, 0.45 µm).
Recommended rates for using hydrogen peroxide
The recommended concentration of hydrogen peroxide for water disinfection varies depending on the intended use and the level of contamination present. For drinking water, the EPA recommends a concentration of at 25 to 50 ppm of residual hydrogen peroxide.
To disinfect, first clean any visible dirt or grime off the area with plain soap and water. Then spray surfaces with a 50/50 mix of peroxide and water.
Chlorine is still one of the most effective killers of algae so doing a super-chlorination of 10-20 ppm of chlorine can go a long way towards wiping out the algae. Liquid chlorine is an ideal shock for algae because it is fast acting and does not add cyanuric acid (CYA) or calcium to the water.
Bleach is great for killing algae (and other organisms that may lurk in your tanks) and for keeping it from coming back.
Hydrogen peroxide causes toxicity via three main mechanisms: corrosive damage, oxygen gas formation and lipid peroxidation. Concentrated hydrogen peroxide is caustic and exposure may result in local tissue damage.
Hydrogen Peroxide VS Chlorine
If you have surface water and need to disinfect it, especially if there is algae, then chlorine is dramatically superior to hydrogen peroxide. However, if you have incredibly high iron or sulfur, chlorine is not a good choice, but hydrogen peroxide is.
If you are treating a sick plant or one infested with insects, use a slightly stronger mixture of one tablespoon of hydrogen peroxide in eight ounces of water. Don't use hydrogen peroxide on your plants more frequently than twice each week. If you make more than you need, you can store it.
Use up to 4 times daily or as directed by your dentist or doctor. Use this product regularly in order to get the most benefit from it. To help you remember, use it at the same time(s) each day. Tell your doctor if your condition does not improve in 7 days or if it worsens.
Also, make sure to rinse thoroughly every time you use hydrogen peroxide. Mouthwash at the same time every day to get the most benefit.
Hydrogen peroxide reacts very fast. It will than disintegrate into hydrogen and water, without the formation of byproducts. This increases the amount of oxygen in water.
Swimming pools are kept usually in range 30-60ppm and hot tubs between 50 to 100 ppm hydrogen peroxide in water. 35% Hydrogen peroxide is extremely corrosive and a strong oxidizer.
Hydrogen Peroxide helps to break down chlorine, but works best in pH levels of 7.0 or higher. Use 7 oz. of Aqua Silk Oxidizer (27% hydrogen peroxide formula) per 10,000 gallons of pool water to lower chlorine level by 3.0 ppm. For spas and smaller bodies of water, use 1 oz.
Calcium Hypochlorite: Also referred to as cal hypo, this chemical is one of the least costly and most convenient ways to shock your pool. It's usually sold in granular form. Needs to be dissolved before you add it to the pool. Must be used after dusk.