Hi Michael,
I am sorry if there is any misunderstanding about the feed and water silo being interchangeable. The holes for the feed ports are 2 3/4' in diameter and the feed silo has a funnel inside.
The water silo has a 3/4' hole for our water ports so they can't be added to turn a feeder into a water silo.
I will be glad to issue a full refund and send a UPS call tag if you would like to return it.
Please feel free to call me on my cell at 910-233-0502 anytime to discuss.
Thanks,
Tom Carter
Tom@coopworxUSA.com