If you have issues with anything you get from RBI, I would recommend talking to Rich about it before you just chalk it up to experience and replace it. My experience has been that he is a very stand up guy and knows customer service...something kind of hard to come by these days. If something he sells you isn't working like it should, he makes it right.
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Are you sure you had the RBI valves? There is definitely a spring in the valve. When you unscrew the two pieces of the valve the spring freely falls out. Here is a link to the valve I'm referencing:
http://www.reptilebasics.com/rodent-watering/rodent-drinking-valve/
I've been using them for a good while now with no issues. I'll keep an eye on them and post an update if they do start leaking.