Check valve on bleach injection not allowing injection

scrupul0us

I have a culligan water treatment system in my home to combat sulfur in my well water.

Recently i noticed the levels of sulfur increasing and upon checking the chlorine values they back 0 parts...

The chem feeder appears to be working OK, when i disconnect the output tube and cycle the system bleach comes out

When I reconnect the tube and cycle the system bleach goes down to the injection well before the check valve BUT it never gets through

I've replaced the check valve twice and verified its not hardened or distorted (the nice Culligan guy that came last time gave me a few extras)

After a cycle if I pull the tube from the injection end and push a small screwdriver through the check valve the remaining bleach goes right in..

Now, the ONLY thing I can think of is if the tube inside the chem feeder (Stenner 85MHP17) has any kind of leak, maybe there isn't enough pressure to force the bleach through the check valve during the cycle?

I'm running a 30/50 pressure switch on the system...

Any words of wisdom?

Thanks