Check Valve

[Rigby]

I'm building a Calcium Reactor and I bought check valves (1/2") from Home Depot and am just wondering if all pvc check valves are all created equal. It seems the ones I see of others who have built Reactors are smaller. Any feedback would be appreciated.
glen

[IFLY2HIGH]

The ones from HD I think are sping loaded. I know the one for my return is, I got it from lowes (3/4). There are some that sell at Mail Order places that are a flapper style. I think there smaller. I can't be sure though.

- Eric