Marc Russo, I am trying to get ahold of you. Please email from another email other than the one Steve checks because I don't think he's giving you my information. I have asked him multiple times to speak with you. This is concerning a product I ordered from your company in February that I have not received and have not been refunded. My email is firstname.lastname@example.org
2003, 2006, 2009, 2016.. lol It is a somewhat useful thread though. I have some tanks that sat a long time in amazingly hard water and vinegar isn't enough. Peroxide should be harmless unless too much undiluted liquid or powder gets in water that has or will contain live fish. Although the powder version is not just pure hydrogen peroxide. That doesn't work chemically. It is sodium percarbonate and breaks down to also produce soda ash which is similar to baking soda.