algae and turtles

Question
I have a new concrete pond apx 7' X 7'oval, a foot of water #do we need more?# with a 8' high water fall with bottom rock layers. Will the waterfall oxidize the water enough.   We want to have only water turtles for now.  We will get the turtles in April.  In the meantime I am afraid to put anything #bleach# in the water #not knowing the right thing for the turtles# so the water is getting pretty murky, with sediment in the bottom.  We have changed the water once already.  How much sediment is too much, how much do the turtles need, and eat.  We were told to use Gentian Violet but can't find anything on it for ponds.  Please advise.. and thank you..

Answer
Most of this depends on what type of turtles you get.  Don't bleach the water.  Turtles like a lot of sediment, at least a few inches.  Again, different turtles eat different foods, but most of them eat some vegetables.  They also need some driftwood so that they can get out of the water when they need to.