We received a really good question the other day concerning the use of hydrogen peroxide H202, and it’s use in ponds and water gardens. Specifically, what about using the drug store liquid peroxide that you normally would use to disinfect scratches and scrapes. So here’s a video that covers the various uses of hydrogen peroxide in ponds.
Long before any commercial products came on the market that contained peroxide, I suspect any good do-it-yourself loving pond owner would have probably tried it for algae control.
You gotta love the open minded experimentors of this world…they move us forward.
With that said, I generally don’t recommend using store bought H202 simply because I try to error widely on the side of caution with such things. First of all, the normal 3% solution is pretty light weight and may not do very much to help with algae. Secondly, a lot of this stuff isn’t just hydrogen peroxide and some will contain stabilizers and additives that I don’t want in my pond.
So that leaves a couple of options.
Of the commercial products, most of them are granulated and whether they are registered with the EPA, or listed as an algaecide or not, they all work in a similar fashion.
Our most popular seller of this type is called Algae-Off and it works as a contact algaecide. We will normally only suggest to use it on rocks, waterfall areas, streambeds, and for spot treating string algae. We don’t find this type of product to be cost effective over large areas of algae, and certainly not on green water problems.
Used as directed is very safe for fish and other plants (however you do want to avoid contact with desired plants) And please pay attention to the following.
Any product that’s designed to kill algae outright, no matter how safe it may be, will create a die off reaction and as the plant dies it will pull oxygen from the water. So, for example, during really hot weather if someone were to try and treat a large algae mass, or green water with peroxide, it’s possible that an oxygen deficit could occur in the pond and kill fish. It wasn’t so much the product that did the damage but in how and when it was applied. So some degree of discretion needs to be applied here too.
Apart from the granulated products, there are also some liquid varieties offered too. And you could also look for a food-grade hydrogen peroxide which is used for cleaning and disinfecting purposes in the food industry. This liquid H202 is very concentrated (35% usuallly) and needs to be handled with care. It can be diluted down to about 10% and sprayed on algae that appears on surfaces and works well for control in that setting. It won’t work well underwater or in the same way that granules might in the water itself.
The best way to locate food grade peroxide is through an online search.
Hydrogen peroxide can be a viable tool for algae control. It must be applied so that it comes in direct contact with the algae that’s being treated. It’s very safe mainly due to the fact that it dissolves or dissipates so quickly, turning into oxygen and water, within just a few minutes.
The only precaution I normally tell people about is to simply make sure that all the granules get dissolved in water and don’t leave any of them lying around. Birds, bees, or pets may come in contact with them and they are caustic in the dry state.