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The old "One-Two Punch" whole tank algae treatment - UPDATED for 2023


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    Oct 29, 2022
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    Miami, FL
    Way back in 2013, on a forum far, far away, DarkCobra posted his "One-Two Punch" whole tank algae treatment. In his words, he described it as:
    In brief: It uses a properly executed H2O2 whole tank treatment, followed by a whole tank Excel treatment, to provide a much greater algicidal effect than either alone; without noticeably increased risk to fauna or plants.
    While we have come a long way since 2013, I think it is valuable to preserve, and even update, this method here on ScapeCrunch.

    Initial Disclaimers:​

    1. Many people feel that this treatment isn't necessary. Focusing on getting your plants healthy and your tank stable will, ultimately, resolve your algae issue. Please consider doing this first before trying this aggressive treatment method.
    2. Algae grew due to one or more issues in your tank. Please address this underlying cause prior to any algae treatment.
    3. Do NOT try this method if you have shrimp or sensitive invertebrates. It has been known to kill them.
    4. API's AlgaeFix is known to also work for stubborn algae. Some say the One-Two Punch treatment is better and less risky.

    In summary, the method is:

    Punch One:​

    • Ensure you have very HIGH flow in your aquarium. Add powerheads, if you have them. High flow is deemed critical for fish health.
    • Remove Marimo balls.
    • Keep the lights on.
    • Remove biological material from your filters (updated for 2023) and store in a way that the bacteria won't die.
    • Add 3% H2O2, at a dosage of 2 tbsp. per 10G of actual tank water volume (excluding substrate, plants, etc.).
    • Allow to circulate for 15 minutes. During this time, redirect flow a few times if possible, to make sure all areas get covered. If you have particular trouble spots, try to ensure they get direct flow during part of the treatment.
    • After the 15 minutes, terminate the treatment. Do at least a 50% water change. Return the tank to its normal configuration, including replacing filter media if it was removed.

    Punch Two:​

    • Add Seachem's recommended initial dose of 5ml per 10G.
    ** Please post further updates to this method if you have any!

    Has anyone tried this in the past? Results?
    Thank you for copying this over. I have used the above treatment in the past; and at that time it did work pretty well.
    I have used a similar treatment using just peroxide. Shut off all filters,remove sponge filters if used. Add 1ml peroxide per gallon of tank volume. Stir gently with hand,or utensil distributing it to all parts of aquarium. Let set for at least one hour. Restart filters,and replace sponge filters. Next day do a 50% water change. It works very well in my experience.