Alright so i am new to this hole caring for birds thing but i now have a dozen ducks and i was going to make a pond out in the yard. i was going to do one that was farly big and have a waterfall with it too. i am going to be doing all the work myself (with the kids) and with all the stuff that i have seen with the liners i dont want to use on of them if i am going to need to spend the $100+ every year. would the ducks be alright in a cement pond or will the ph in it be to high like it is with fish? i dont want to harm the ducks but i do want them to have a place to go swimming.