Re: Cleaning a stagnant pond
The pond is the easy part, though even taking care of the garden isn't that big a deal, it's more elbow grease than anything else.
With the pond, if you want to save the frogs, then you'll have to go to a pond shop and purchase algae inhibitors which are specifically designed NOT to harm aquatic life. If you don't care about what's in there now, you have two options, one is to pour 1 cup of liquid bleach per 100 gallons of water, or a more natural means will be to use hydrogen peroxide. The nice thing about peroxide is that it won't harm domestic animals, even in high concentration, and it will inhibit algae growth far better than chlorine without harm to the environment. You can even use peroxide with aquatic life, but you have to use it carefully and build up to the dosage required to maintain a clean pond environment yet still support aquatic life. Plants don't care so much, but animals such as fish and frogs don't like high doses of peroxide. I will say this much, however, they can tolerate peroxide far better than they can chlorine which is a chemical.
I've used peroxide in my 125 gallon pond for years, up until we stocked it with mosquito fish. Prior to the fish, less than 1/4 cup of 35% peroxide into the pond per week kept it crystal clear and mosquito free. When we decided to put the fish in and started to get a few frogs, we dropped the peroxide content down to 2 tablespoons into the 125 gallon pond and the fish and frogs still didn't like it. If you do the math, 2 Tbs in 125 gallons is nearly imperceptible, yet it was enough to adversely affect the aquatic life.
Also, since there is little to nothing as far as aquatic life goes, in the pond already, you can drain and clean the pond, refill with fresh water, and then maintain it with pond additives as necessary to sustain aquatic life. Sometimes it's easier to start from scratch than to try to work with what you have.
I suffer from CDO ... Its like OCD, but in alphabetical order, LIKE IT SHOULD BE!!!