I accidentally knock over 15 mls of peroxie in 26 gallon do I do a water change

[Formulator]

There’s nothing you can do now. Don’t bother with water changes or carbon. All H2O2 has decomposed into water and oxygen.

 

[KrisReef]

Do I assume correctly that this was drug store 4% peroxide? If so, your zoas may close up for a day or two and some sensitive SPS may be unhappy. I don't think your fish will be affected. If it is a more concentrated peroxide solution, I'd be concerned and do a water change.

You could do a 20% water change. if it were my tank, I'd wait and see. I routinely used 10 mL of 4% peroxide in my 29g nano for cyano with no ill effects.

I'd also not worry about stirring. That will have diluted the peroxide quickly and allowed it to interact with more of the dissolved organic material and be destroyed.

Same question, but I was thinking they sell 3%.

Lowes and Home Depot sell 12%! I am glad this was not that>

 

[Johnnyrainbowreefer]

Nope you’re fine. I am currently dosing 10 mls nightly for a small Dino outbreak. It breaks down within ten minutes.