Pond Supply

We don’t keep the pump going all the time so I am concerned with mosquitoes forming when the water is stagnant, sometimes for days. Also, my fountain is two tiered where the water runs up from the main section and pours down from the top part. I have chosen to put a basket of flowers up there and I am wondering if the mosquito dunks in the water would be harmful to the flowers. It says they are safe for humans, pets and wildlife so I’m not sure if they are also safe for plants.

Thanks in advance! I’m tired of getting attacked by mosquitoes every time I sit outside.