Water Gardening: DRH2 picture (Peroxide safe for fish and plants?)
In reply to: Peroxide safe for fish and plants?
Forum: Water Gardening
The typical range of doses used are 1-2 pints per 1000 gallons using 3% hydrogen peroxide with a repeat dose anywhere from 3 days to 1 week if necessary to as high as 1 pint per 100 gallons. Having said that you would decrease the volume added if you somehow got your hands on some of the commercial material (as used in Spas) which can be 10-12% or the industrial strength 'stuff' that can be quite high conc. Then all you have to do is proportion it to the size of your pond and the concentration of the hydrogen peroxide. If anyone would like I have a little spreadsheet that you can use - all you have to do is put in the volume of your pond and the % hydrogen peroxide and it will calculate the volume you need to measure; just drop me an e-mail. I will attempt to figure out a way to post it otherwise feel free to contact me.
As to removing as much of the string algae as possible: when you kill off the algae you're releasing a significant amount of organic matter into your pond. While the initial dose of hydrogen peroxide will temporarily increase the oxygen levels the elevated oxygen levels can be then used up over the next day or two as the organic matter is broken down (typically referred to as BOD or Biochemical Oxygen Demand). If your water temperature is warm, hence oxygen solubility is low and/or the rate of aeration (oxygen input) is not very high you could potentially run the risk of creating low oxygen conditions in your pond. I highly doubt this would be a factor if your pond temperature is below say 75°F and with any type of waterfall or spitter working. But if you're concerned then clean out as much as possible by hand using a stick or a brush on a stick or pole - I personally like a color-coordinated toilet bowl brush!!
Safety. Hydrogen peroxide is a strong oxidizer that's how it does it's business. It will bleach your hair and it will kill bacteria and string algae. However, as chemicals go it is probably one of the safer ones to 'play' with for the average home owner/pond owner ranking close to 'safe-use/potential toxicity' of salt. As to problems for you pets - remember that one of the common household uses for hydrogen peroxide is as a mouthwash (diluted 1:1 with tap water) in which you would inadvertantly swallow 'some' - it's often recommended by physicians or dentists to help with infections of the mouth. But that doesn't mean, in my book, that I'd go giving Fido a tablespoon or two in his drinking bowl!! I would not worry about animals or birds taking a drink out of a pond once it's been treated even if you're dosing at the rate of 1 pint per 100 gallons (which some have used).