Mark
I put bluing in all the animals water as an antibacterial. I bought all my Dura waterers except for 1 at auctions. The 1 came from a friend.
They all were for sale because they could not get them to stop overflowing. A few of them were kept outside, & the plug cap was brittle & broke soon after I got them.
I was using one cap for several waterers, carrying it around with me as I was filling them. One day I emptied a bluing bottle & just happened to try the cap, cause I forgot to take the plug cap with me. It fit!!
Now I don't have to carry one with me anymore. That is good, I was having to go back & forth to pens all the time cause I couldn't remember that darn cap!!!
I looked at the waterers you provided links to.
They both look good, but I think they all work on the same principle as the Dura Font. I like the round concept, I bet they are easier to clean. I have been looking at the black ones too, but I do like to see at a glance the water level.
If you get any of these, please let us know how they work for you. Oh, the Dura...you have to screw the lid on very tightly too.
Jean