Thanks for all of your tips. I am trying to see it the way some of you mentioned, that it doesn't look that bad and it is beneficial. Well my pond plants are finally coming back in (I can see them sprouting from the bottom of the pond), so hopefully this will give a little more shade. Plus I have a birch and maple somewhat nearby enough that in a few years they might give more shade as they grow. You were right that scrubbing is a lot of work and really does nothing. I looked into one of those algae eater fish, but I really don't want to have to bring it in over winter. A friend recently gace me a cup of barley pellets to try out, so maybe I'll try that this weekend. Some great news though... we saw 5 American Toads were having a nice time together in there this past week, calling so loud all day and night. Now we have tons of eggs in there! I attached a link to a picture. Maybe they can eat some algae when the eggs hatch. Here is a link that might be useful: toad eggs

Hydrogen peroxide is so safe I would say use it as often as necessary. I use it in my pond on a regular basis with no harmful effects to fish or plants. I watch for signs that algae is starting to grow and add as needed. I find if I wait too long it's a bit more difficult to get rid of the algae again.

Hi hardin, Here is a post I saved from another forum because I thought the responding poster was very knowledgable. Also this was posted on a public forum so I do not think the posters would mind it being used again. I have never tried this and personally I am very cautious and do not add chemicals to the pond unless necessary. Regards, Lisa Originally Posted by BillJ Roddy,how much HP can safely be added to 4000 gal.?And how often?Doesn't it temporarily lower ORP?If so,how long before the Orp returns to normal,or does this only occure when neutralizing PP? Not even close to giving up yet. Thanks,Roddy Bill How much hydrogen peroxide can be safely added is a function of the concentration of the hydrogen peroxide and the robustness of the pond's biofilter. I add typicallly 50 ppm to 100 ppm hydrogen peroxide when I add it. That kills algae and cleans water and cleans the bottom of the pond just swell, and doesn't hurt fish. It doesn't hurt my lava rock fountain, biofilters in my water gardens. Ammonia and nitrites stay non-detectable. I don't turn off the biofilter flow when dosing the hydrogen peroxide. 100 ppm hydrogen peroxide is a quart per 1000 gallons using the 35% hydrogen peroxide strength, or 11 quarts per 1000 gallons of 3% hydrogen peroxide from Walmart (or other Drug store sources). While that is what I dose, since it is also a documented treatment that kills several of the common fish parasites, I wouldn't recommend doses much higher. The hydrogen peroxide is gone in 24 hours, most of it is gone in about 8 hours. When you first dose it, the sediment boils up from the bottom of the pond so have a fine net to remove it from the surface for the first 30 minutes or so after dosing the hydrogen peroxide (if your pond bottom is not clean!). Hydrogen peroxide temporarily lowers ORP to around 150-180 millivolts. I have learned to ignore that effect.

The peroxide sold at the drugstore is heavily diluted. I think it's 98% water. Pure hydrogen peroxide is very dangerous. It's been used as rocket fuel. I understand that big farming operations use something called urea hydrogen peroxide. This also has to be diluted before it can be applied to crops. One source I read said that a container of pure peroxide could explode if a drop of blood fell into it. By the way, urea hydrogen peroxide is also used to bleach hair. One time, just out of curiosity, I tried watering a plant with drugstore peroxide straight out of the bottle. Not a good idea, it turns out. It foamed up so much that it pushed half the soil out of the 4-inch pot. I have heard, however, that 2% peroxide can be added to water and then used to water plants. It's supposed to help plants recover from over-watering. I've no idea if it works.