Stock tank defense in duck ponds?

[mamdoe]

I am planning on getting a large galvanized stock tank to use as a pond for my ducks. Was just reading about Stock Tank Defense tablets, said to keep water clean and clear, yet safe for animals to drink.
Anyone ever use these?
Thanks!

 

[Kevin565]

Are they just for keeping the water clear or for mosquito control as well? I don't think the tablets will have much effect since ducks produce so much waste.